Dissertations / Theses: 'Eliciteur'

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Kati, Djamel Edine. "Mécanismes de défense chez les végétaux et notion d'élicitation : cas de Cucumis melo et d'un Stimulateur des Défenses Naturelles le «FEN560»." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20007.

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Nos travaux de recherches de thèse portent sur une étude comparative entre le déclanchement des mécanismes de défense in planta de la plante de melon après élicitation biotique, et un traitement avec un produit ayant des propriétés de Stimulateur des Défenses Naturelles (SDN). Le pathosystème étudié est Cucumis melo - Fusarium Oxysporum melonis. L'éliciteur abiotique SDN utilisé codé FEN560 est un extrait de graines de fenugrec (Trigonella foenum-graecum). Les principaux travaux sont : 1) L'analyse des activités enzymatiques relatives au stress et caractérisation d'enzymes PR. 2) L'étude des métabolites du métabolisme secondaire, notamment la production l'accumulation des composés organiques volatiles (COV). 3) Une étude de l'expression de gènes candidats impliqués dans la production de ces PR-protéines et/ou dans les voie de signalisation est aussi entreprise ; Les principaux résultats se traduisent par (i) une précocité et intensité de l'induction des activités enzymatiques étudiées pour les deux variétés et pour les organes d'un même plant (ii) Le priming est généralement observé au niveau du site de la seconde élicitation (infection FOM) avec une induction remarquable des PR-protéines. (iii) L'élicitation est Systémique, car l'induction se transmet mais à moindre intensité sur les intervalles de temps étudiés. (iv) L'augmentation de l'émission des COV coïncide avec l'induction de la LOX. Il est aussi noté l'émission de nouvelles molécules connus par leurs propriétés antibiotique ou répulsive des insectes herbivores ou attractive des prédateurs d'insectes herbivores. Les résultats sur les expressions des gènes candidats sont corrélés avec les activités enzymatiques et la production des composés organiques. Il en est ressorti que l'induction de la résistance par le traitement par pulvérisation de FEN560 est similaire au phénomène de « primig » dans la résistance systémique induite This work is a comparative study between defense mechanisms in melon plant induced by biotic elicitor and treatment by plant extract having simulative proprieties of plant defense mechanisms. The studied pathosystème is Cucumis melo - Fusarium oxysporum fsp melonis. The used plant extract elicitor is named FEN560, it is from fenugreek seeds (Trigonella foenum-graecum). The main works were: 1) Analysis of the enzymatic activities relating to the stress and characterization of PR-proteins sch as peroxidases and chitinases. The lipoxygenase (LOX), the key enzyme of oxylipins biosynthesis and phenylalanine ammonia-lyase, the key enzyme of the phenylpropanoids pathway, were also studyed. 2) The study of the metabolites of the secondary metabolism, in particular accumulation of volatile organic compounds (VOC). 3) A study of expression candidate genes implied in the production of Pr-proteins and the induced resistance pathways is also undertaken. The main results: (i) precocity and intensity of enzymatic activities induction for the two varieties after inoculation of pretreated plants (ii) the priming is generally observed in the site of the second elicitation with a remarkable induction of PR-proteins. (iii) The elicitation induced by FEN560 is systemic; because induction is transmitted between roots and shoots (iv) The modification of VOC emissions coincides with the induction of the LOX activity. It is also noticed the emission of new molecules known for their antibiotic properties or repulsive of the insects herbivorous or attractive of predatory of herbivorous insects. The results on the genes candidates' expression are in general correlated with the enzymatic activities and the production of the volatile organic compounds through LOX activity. In brief, the induction of resistance by the treatment by FEN560 is similar to the phenomenon of "primig" in induced systemic resistance

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DUBOIS, DAUPHIN ROBIN. "Contribution à l'étude des propriétés phytoactives des engrais foliaires d'algues marines : identification d'un signal eliciteur." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10110.

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Les bases moleculaires des proprietes phytoactives de polysaccharides d'algues marines ont ete analysees : en particulier, le potentiel eliciteur d'une creme d'algue ga14 (laboratoires goemar, st malo) preparee a partir d'ascophyllum nodosum ont ete rapportees a un composant fucoidane. Les proprietes biologiques de ce produit nomme pha-ac ont ete testees sur des suspensions de protoplastes ou de cellules de rubus fruticosus l. Pha-ac initialise rapidement des reponses physiologiques impliquees dans la defense des vegetaux (activation de phenylalanine-ammoniac lyase, de proteines liees a la pathogenese (d-glycohydrolases, inhibiteur de protease. . ) ou bien dans leur croissance et/ ou developpement (induction d'amylase, d'inhibiteur de protease bifonctionnel, elicitation de composes benzoiques. . . ). L'identification (par hplc-pda) des produits reactionnels issus d'un complexe membranaire pal elicite par pha-ac ac a des cinnamates (acides p-coumarique, ferulique) et a des benzoates (acides vanillique et isovanillique, aldehydes 3-methoxybenzoique, salicylique, syringique et vanilline) dont certains sont connus pour leur fonction hormonale a ete realisee. L'etude des relations structure-activite biologique, de la modulation des reponses par des inhibiteurs transcriptionnels/ post-transcriptionnels fait apparaitre que pha-ac est bien un signal eliciteur. Les retombees biotechnologiques du travail sont abordees avec la possibilite d'integrer le fucoidane (sous la forme de sa structure efficace ou de derives ou d'analogues) dans la formulation de produits phytosanitaires ou de biostimulants non toxiques pour l'environnement.

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Varet, Anne. "Caractérisation de deux gènes d'arabidopsis thaliana possédant des similarités de séquence avec le gène NDR1 d'arabidopsis et de gène HIN1 du tabac." Paris, Institut national d'agronomie de Paris Grignon, 2002. http://www.theses.fr/2002INAP0007.

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Le gène NDR1 est requis pour la résistance à P. S. Pv. Tomato DC3000 exprimant avrB, avrRpm1, avrRpt2 ou avrPphB et à certaines souches de Peronospora parasitica chez Arabidapsis. L'expression de NDR1 est induite par la bactérie Pseudomonas syringae et la proteine NDR1 partage des similarités de séquences avec le produit du gène HIN1 du tabac. L'expression du gène HIN1 est induite par les harpines et des bactéries élicitant la réaction d'hypersensibilité chez le Tabac. Les fonctions biochimiques de NDR1 et HIN1 restent à déterminer. Des recherches dans les banques de données révèlent qu'il existe chez Arabidopsis une large famille de gènes présentant des similarités de séquences avec NDR1 et HIN1 (gènes NHLs pour NDR1/HIN1-like). Dans ce travail, nous avons caractérisé deux de ces gènes, NHL3 et NHL25, dont l'expression est induite lors d'interactions incompatibles impliquant la bactérie Pseudomonas syringue pv. Tomato DC3000 et l'écotype Columbia d'Arabidopsis thaliana. L'analyse de leur profil d'expression chez des mutants d'Arabidopsis affectés dans certaines réponses de défense, a mis en évidence que les deux voies de transduction conduisant à l'accumulation de leurs transcrits suite à la reconnaisance d'un éliciteur bactérien sont probablément nouvelles. L'expression de NHL25 est induite par des éliciteurs race-spécifiques et par l'éliciteur race-non-spécifique NPP1, qui provoque l'apparition de nécroses semblabes à la réaction d'hypersensibilité chez Arabidopsis. Ainsi, nous avons proposé que le gène NHL25 soit considéré comme un marqueur de la mort cellulaire. L'accumulation des transcripts de NHL3 semble être réprimée par un suppresseur secrété par la bactérie Pseudomonas syringae pv. Tomato DC3000 via le système de sécrétion de type III. D'autre part, la surexpression de NHL3 dans des plantes d'Arabidapsis a révélé l'existence d'une corrélation stricte entre l'élévation des niveaux de transcrits de NHL3 et l'augmentation de la résistance à Pseudomonas syringae pv. Tomato DC3000, et nous avons montré que NHL3 est une protéine membranaire glycosylée. L'ensemble de ces résultats indique que NHL3 contribue à la résistance aux bactéries chez Arabidopsis. En conclusion, ce travail a révélé des rôles distincts pour les gènes NHL3 et NHL25 dans les réponses de défense chez Arabidopsis.

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TRENTIN, FLORENCE. "Analyse de la specialisation parasitaire de p. Parasitica a l'egard du tabac; etude de l'implication d'un eliciteur proteique." Paris 11, 1991. http://www.theses.fr/1991PA112374.

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A l'aide d'un test original d'inoculation racinaire sur plantules, l'etude du comportement de phytophthora parasitica a l'egard du tabac a montre l'existence de 3 types d'isolats, 1) des isolats non parasites du tabac secretant une proteine, la parasiticeine elicitrice de reactions de defense et d'hypersensibilite chez le tabac; 2) des isolats specifiquement infeodes au tabac ne secretant pas de parasiticeine; 3) des isolats pathogenes a la fois sur tabac, illet et/ou tomate; ils produisent de la parasiticeine et ont une agressivite plus faible que les precedents. L'homogeneite taxonomique de ces differentes souches a ete etablie par l'absence de polymorphisme de l'adn repetitif, (nouvelle technique de caracterisation des especes de phytophthora) et confirmee par l'obtention d'hybrides. L'expression du pouvoir pathogene et la production de parasiticeine a ete etudiee chez les produits de la reproduction sexuee. Quelques recombinants, pathogenes et produisant la parasiticeine ont ete obtenus. Aucun ne manifeste une forte agressivite sur tabac. Le gene de la parasiticeine pourrait etre present mais non exprime chez les isolats specialises a l'egard de cette plante. Malgre les difficultes d'apprehender par un meme test, l'envahissement des tissus et les reactions necrotiques induites par la parasiticeine, ainsi que les problemes lies au mode de reproduction de ce champignon heterothallique, nous pouvons conclure que l'absence de production de parasiticeine est un facteur specifique d'agressivite a l'egard du tabac qui, de facon encore inexpliquee, s'accompagne d'une specialisation a l'egard de cet hote

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BAILLIEUL, FABIENNE. "Mecanismes de defense des plantes vis-a-vis des agents pathogenes : etude de la reaction d'hypersensibilite a l'aide d'un modele d'interaction plante-eliciteur." Université Louis Pasteur (Strasbourg) (1971-2008), 1996. http://www.theses.fr/1996STR13001.

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La reaction d'hypersensibilite (rh) est un mecanisme complexe de defense induit par une plante suite a l'infection par des agents pathogenes de nature variee. La rh implique la mort de cellules vegetales, l'expression de toute une batterie de reponses de defense, dont l'induction d'une resistance systemique acquise, regulees par des signaux endogenes. L'interconnection entre ces differents evenements est encore mal connue ainsi que leur base moleculaire. Une glycoproteine et deux holoproteines de la famille des elicitines ont ete isolees du champignon phytophthora megasperma h20 et caracterisees: elles sont serologiquement reliees, presentent des homologies de sequence, et sont produites par plusieurs especes du champignon. Ces proteines induisent une rh chez le tabac. Les mecanismes moleculaires de la rh induite par la glycoproteine ont ete particulierement etudies. Une analyse fine a revele une expression spatio-temporelle differentielle de genes de defense. Trois classes de genes ont ete definies: les genes dont l'expression a lieu rapidement dans les cellules percevant l'eliciteur mais avant leur mort ; les genes s'exprimant plus tardivement dans les cellules situees au-dela des precedentes apres leur mort ; les genes du metabolisme oxydatif. La production d'acide salicylique est induite, qui pourrait etre un signal important dans la regulation de la deuxieme classe de genes. L'expression du processus de mort n'est pas necessaire a l'induction de tous les genes de defense, mais semble indispensable a la production des signaux mobiles regulant l'expression des defenses a courte et longue distances. Ni la glycoproteine, ni l'acide salicylique ne sont le signal migrant a courte distance. Par contre, des formes activees de l'oxygene reguleraient negativement un tel signal. Le clonage du gene de la glycoproteine a ete entrepris dans le but de tester une nouvelle strategie de protection des plantes contre un large spectre de microbes et consistant a faire exprimer par une plante un tel eliciteur de maniere controlee

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Koçi, Rromir. "Valorisation d'un co-produit d'extraction de l'agar à partir de l'algue rouge Gelidium sesquipedale en tant que stimulateur de défenses de plantes. Caractérisation chimique et évaluation de ses propriétés en vue d'applications en biocontrôle." Electronic Thesis or Diss., Limoges, 2023. http://www.theses.fr/2023LIMO0007.

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Les co-produits industriels de la première étape d’extraction d’agar (de l’algue rouge Gelidium sesquipedale) constituent au sein de l’entreprise SETEXAM des volumes importants potentiellement valorisables. L’objectif de ce travail est de démontrer qu’ils peuvent être utilisés en tant qu‘éliciteur, ou stimulateur des défenses naturelles (SDN). D’abord, la composition élémentaire du co-produit alcalin a révélé une teneur en minéraux de 44 % (Na, K éléments majeurs) avec des traces de métaux lourds, mais en dessous de la limite autorisée. Les principaux composés organiques détectés sont des glucides (12,5 %) et une fraction riche en floridoside a été obtenue. Ce composé a été identifié par une méthode originale, la CPG-MS. Le co-produit alcalin, recyclé au cours du procédé industriel, voit sa teneur en glucides diminuer avec l’augmentation du nombre de cycles. Ces co-produits, appliqués sur des plants de tomates cultivées en serre sous stress biotique, sont capables de stimuler des réponses de défense (activités enzymatiques, expression des gènes). La dose optimale (50 mg.L-1) a été déterminée ainsi que les conditions d’applications et la durée d’activation des réponses. En plein champ, les co-produits ont été testés sur vigne et sur tomate, pour leur capacité à réduire les symptômes du mildiou, ou de la cladosporiose. Des résultats prometteurs ont été obtenus comparés à des éliciteurs déjà commercialisés, en conditions de pression modérée. Le co-produit issu de la première étape d’extraction industrielle d’agar a montré une activité comme SDN et peut constituer une solution de protection des cultures permettant une réduction des pesticides pour une agriculture durable et plus respectueuse de l’environnement. Ce travail constitue une base pour un dossier d’homologation du produit qui transformerait ces co-produits de coût en ressource pour l’entreprise The industrial by-products of the first step of agar extraction (from red alga Gelidium sesquipedale) constitute large volumes at SETEXAM company that might be valorized. The objective of this work is to prove that they can be used as elicitor, or plant defense stimulator (PDS). Firstly, the elemental composition of the alkaline by-product revealed a mineral content of 44% (Na, K major components) with heavy metal traces, but under authorized limits. The principal organic components detected are carbohydrates (12.5%) and a fraction rich in floridoside was obtained. This molecule was identified with an original method, through GC-MS. The alkaline by-product, recycled through the industrial process, has its carbohydrate content diminished as the number of cycles increases. These by-products, applied on tomato plants grown in greenhouse under biotic stress, are capable of stimulating defense responses (enzymatic activities, gene expression). The optimal dose (50 mg.L-1) was determined together with the application conditions and time span of responses. In field, the by-products were tested on grapevine and on tomato, for their capacity to reduce downy mildew, or leaf mold symptoms. Promising results were obtained compared to already commercialized elicitors, for moderate disease pressure. The by-product obtained from the first step of industrial agar extraction showed a PDS activity and can be a solution for culture defense allowing a reduction of pesticides for a durable and environmentally friendly agriculture. This work is a base for a homologation file of the product that would transform these by-products from cost to resource for the company

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Boissy, Guillaume. "Structure cristalline resolue a 2,2 angstrom par la methode mad d'un eliciteur fongique secrete par phytophthora cryptogea et membre d'une nouvelle famille de proteines necrotiques." Paris 6, 1996. http://www.theses.fr/1996PA066049.

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Les elicitines constituent une nouvelle classe de proteines necrotiques qui sont secretees par les champignons du genre phytophtora et pythium, parasites de nombreuses especes agricoles. Ces proteines de 10 kda induisent des necroses foliaires dans les plantes infectees et provoquent une reaction d'hypersensibilite conduisant au developpement d'une resistance systemique acquise contre une gamme d'organismes pathogenes bacteriens et fongiques. La determination de la structure cristalline de la beta-cryptogeine (cry), secretee par phytophthora cryptogea, a ete entreprise pour identifier les motifs structuraux importants pour l'activite necrotique. L'absence d'homologie de sequence avec des proteines de structure connue nous a amenes a utiliser la methode du remplacement isomorphe. La recherche de derives lourds isomorphes n'a fourni qu'un derive platine de faible pouvoir phasant. Nous avons ainsi resolu la structure de la cry par la methode de phasage mad (diffusion anomale a plusieurs longueurs d'onde). Nous avons collecte quatre jeux de donnees au voisinage du seuil d'absorption liii du platine sur la ligne d2am de l'esrf (grenoble). L'affinement des parametres par maximum de vraisemblance a l'aide du programme sharp et l'addition des donnees d'un cristal natif au calcul des phases ont ete decisifs pour l'obtention d'une carte de densite electronique interpretable. Le modele atomique a ete affine a 2,2 angstrom. Le repliement de la cry ne montre de similarites de topologie avec aucune autre proteine. La structure consiste en six helices et un motif en bec-de-cane, dont la sequence est hautement conservee dans la famille des elicitines, compose d'un feuillet beta antiparallele et d'une boucle omega. On suppose que ce motif est un site majeur de reconnaissance pour un recepteur ou/et un ligand potentiel(s). Nous avons identifie deux autres sites de liaison semblant etre correles au niveau d'activite necrotique des elicitines

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Castilleux, Romain. "Role des extensines et leur glycosylation dans la défense racinaire." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR099/document.

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Les extensines sont des glycoprotéines pariétales appartenant à la famille des HRGPs (Hydroxyprolin-rich glycoproteins) impliquées dans plusieurs fonctions telles que la croissance, le développement et la défense des plantes contre les pathogènes. Toutefois, leur mode d’action dans la réponse immunitaire végétale n’est pas encore bien connu et reste à élucider. Les extensines interviennent dans le renforcement de la paroi, un des premiers remparts cellulaires contre les pathogènes, en se liant entre elles de manière intra- et intermoléculaire. Ce « cross-linking » est catalysé par des enzymes peroxydases spécifiques et nécessite une correcte conformation des extensines, laquelle est conférée par leur partie glycosylée. Dans ce projet de thèse, nous avons donc entrepris d’étudier l’impact de la glycosylation des extensines sur la défense racinaire et tenté de caractériser, de manière préliminaire, des peroxydases potentiellement impliquées dans le « cross-linking » chez Arabidopsis thaliana. Des techniques d’immunocytochimie réalisées sur une sélection de mutants affectés dans la glycosylation des extensines ont révélé une modulation de la distribution des extensines dans la racine d’A. thaliana en réponse à une élicitation avec un peptide bactérien, la flagelline 22. L’un des résultats majeurs de cette étude a été de montrer l’importance de l’arabinosylation des extensines dans la colonisation de la racine par l’oomycète pathogène Phytophthora parasitica. Ainsi, l’ensemble de ces résultats nous apermis d’élaborer un modèle proposant d’illustrer l’importance de l’arabinosylation des extensines dans l’organisation et l’architecture de la paroi, modulant ainsi l’adhésion du pathogène sur les cellules de la racine et influençant in fine la colonisation de cette dernière Extensins are cell wall glycoproteins involved in various biological processes including plantprotection. However, their mode of action in plant immunity response is not clearly established and remains to be elucidated. Extensins are able to strengthen the cell wall, one of the first cellular barriers against pathogens, through intra- and intermolecular cross-links. This cross-linking is catalysed by specific peroxidase enzymes and requires a correct conformation of extensins conferred by their glycan moiety. This PhD project aimed to investigate the impact of extensin glycosylation in root defence and to characterize, as a preliminary study, the peroxidases potentially involved in the extensin crosslinking in Arabidopsis thaliana. Through immunocytochemistry techniques on mutants impaired withextensin glycosylation, we have revealed that a modulation of extensin distribution occurs in A. thaliana root in response to elicitation with the bacterial peptide, flagellin 22. We have also showed that extensin arabinosylation plays a major role, although probably indirect, in the root colonization by the pathogen oomycete Phytophthora parasitica. We have therefore elaborated a model proposing to illustrate the importance of extensin arabinosylation in the cell wall organization and architecture,modulating pathogen adhesion on root cells and influencing in fine root colonization

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Larroque, Mathieu. "Mécanismes de surveillance de l'intégrité pariétale et rôle dans l'induction des réponses de défense chez les plantes." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1728/.

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Les oomycètes sont des organismes filamenteux eucaryotes distincts phylogénétiquement des champignons, dont la plupart sont phytopathogènes. CBEL est une glycoprotéine pariétale de l'oomycète Phythophthora parasitica, pouvant se lier à la cellulose et induire l'expression de gènes de défense ainsi que la mort cellulaire chez la plante modèle Arabidopsis thaliana. Cette protéine est constituée de deux régions séparées par une région charnière riche en thréonine proline. Chaque région protéique présente un motif de liaison à la cellulose (CBM1) et un motif PAN-Apple impliqué dans des interactions protéines/protéines ou protéines/polysaccharides. Ce travail de thèse visait à décrypter les mécanismes moléculaires impliqués dans la reconnaissance de CBEL par les végétaux. Dans un premier temps, une analyse in silico a permis de dresser le répertoire complet des protéines eucaryotes à motif CBM1. A contrario des champignons, les oomycètes expriment majoritairement des protéines à motifs CBM1 en association avec des domaines non-catalytiques, suggérant un rôle particulier pour ces protéines chez les oomycètes. Bien que la signature protéique des CBM1 d'oomycètes soit distincte de celle des champignons par la position des cystéines impliquées dans le repliement du domaine et la nature des acides aminés aromatiques responsable de la fixation de la cellulose, la modélisation du CBM1 de CBEL a révélé qu'il pouvait s'associer à la cellulose de façon similaire à un CBM1 fongique. Cette étude a montré que les protéines à domaines CBM1 d'oomycètes sont distinctes de celles des champignons, et présentent une histoire évolutive distincte. Dans un second temps, une production en masse de l'éliciteur a été réalisée dans la levure Pichia pastoris. La protéine hétérologue CBEL conserve les activités biologiques de la protéine native, ce qui a permis une approche de criblage de lignées d'A. Thaliana pour préciser les mécanismes moléculaires impliqués dans sa reconnaissance. De façon surprenante, les réponses de défenses induites par CBEL chez Arabidopsis sont sujettes à une forte variabilité naturelle. La production d'espèces activées de l'oxygène (ROS) liée à la NADPHoxidase est apparue indépendante de la mise en place de la mort cellulaire. En réponse à CBEL, ces deux voies de signalisations agissent en synergie dans l'activation de l'expression de gènes chez A. Thaliana. Enfin, l'utilisation de mutant d'A. Thaliana a montré l'implication de récepteurs like kinase tels BAK1/SERK3 dans la réponse à CBEL. Cette étude a permis de proposer un modèle d'interconnexion des voies de défenses en réponse à CBEL chez A. Thaliana Oomycetes are filamentous eukaryots phylogenetically distinct from fungi and most of them are plant pathogens. CBEL is a cell wall protein of the oomycete Phythophthora parasitica, that is able to bind cellulose and induce defense genes expression as well as cell death on the model plant Arabidopsis thaliana. This protein is constituted of two distinct regions linked by a Thr/Pro rich linker. Each region owns a cellulose binding module (CBM1) and a PAN-Apple domain involved in protein/protein or polysaccharides/proteins interactions. This thesis work aimed at deciphering the molecular mechanisms involved in the recognition of CBEL by plants. In a first time, an in silico analysis allowed us to list the complete repertory of eukaryotic proteins containing CBM1. In contrary to fungi, oomyctes mainly express CBM1 domain associated to non-catalytic domain, meaning a specific role for CBM1 in oomyctes. Although oomyctes CBM1 pattern differ from fungal one on position of critical cysteins for correct folding and aromatic amino acids involved in substrate binding, the modelisation of CBEL's CBM1 revealed it could bind cellulose in a similar way compared to fungal CBM1. This study showed that CBM1 proteins from oomyctes differ from the ones in fungi that is probably the consequence of different evolutive histories. In a second time, mass production of the elicitor was performed in the yeast Pichia pastoris. Heterologous protein CBEL keep similar biological activities compared to the native protein that allowed to screen A. Thaliana lines for identifying molecular players involved in its recognition. Surprisingly, CBEL-induced responses CBEL in Arabidopsis suffer from a strong natural variation. Reactive oxygene species production linked to the NADPHoxidase was independent on the set up of cell death. In response to CBEL, these two signaling pathways act in synergy on defense genes expression in A. Thaliana. Indeed, the use of A. Thaliana mutants showed that receptor like kinase as BAK1/SERK3 were involved in the response to CBEL. This study enabled us to draw a model of the defense signaling network in response to CBEL in A. Thaliana

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Cosse, Audrey. "Analyse du transcriptome des réponses de défense de l'algue brune Laminaria digitata." Phd thesis, AgroParisTech, 2007. http://pastel.archives-ouvertes.fr/pastel-00003673.

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Alors que la base des interactions hôte-pathogène chez les plantes terrestres sont désormais très bien décrites, que ce soit au niveau physiologique, métabolique ou moléculaire, chez les macroalgues marines les investigations n'en sont qu'à leur début. Chez l'algue brune L. digitata, les études sur les réponses de défense suite à l'élicitation par les oligoguluronates, ont permis d'appréhender la transduction du signal conduisant à la production d'un burst oxydant, ainsi que la mise en place tardive de la résistance. Le métabolisme halogéné est particulièrement actif chez cette algue. Il semble être impliqué dans les réponses de défense comme en témoigne l'émission d'iode moléculaire et de composés organiques halogénés volatils, suite à l'élicitation par les oligoguluronates. Dans ce contexte, j'ai étudié la régulation du transcriptome de L. digitata en réponse à l'élicitation par les oligoguluronates, par hybridation soustractive suppressive, macroarray et PCR Quantitative. J'ai ainsi identifié dix gènes codant notamment des haloperoxydases, des thiorédoxines et des enzymes de la voie des pentoses phosphates. L'induction de ces gènes suite à l'élicitation suggère une gestion originale du stress oxydant chez L. digitata. L'implication du métabolisme halogéné dans les réponses de défense a été mise en avant par l'expression différentielle de certains gènes codant des haloperoxydases. La régulation spécifique de certains de ces gènes apporte la première preuve expérimentale que les différents membres d'haloperoxydases ont évolué vers des fonctions biologiques spécifiques. L'identification de ces gènes comme marqueurs moléculaires des réponses de défense a permis d'établir la première modélisation de la signalisation intracellulaire conduisant à l'activation de gènes de défense de L. digitata et de souligner le rôle du peroxyde d'hydrogène dans plusieurs voies distinctes. Les outils développés et les marqueurs moléculaires identifiés permettront d'approfondir la compréhension des réponses de défense des macroalgues dans le contexte des interactions biotiques et de la signalisation à distance.

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11

Khatib, Moustafa. "Etude de l'effet de l'éliciteur CBEL de phytopthora parasitica var, nicotianae infiltré ou produit in planta chez Arabidopsis thaliana et nicotiana tabacum." Toulouse 3, 2004. http://www.theses.fr/2004TOU30038.

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Phytophthora parasitica var. Nicotianae (Ppn), un Oomycète parasite du tabac, produit in vitro et in planta une glycoprotéine pariétale nommée CBEL pour 'Cellulose-Binding Elicitor Lectin'. CBEL est constituée de deux domaines en répétition directe contenant chacun un motif de fixation à la cellulose (CBD), séparés par une région riche en thréonine et proline. En accord avec cette structure, CBEL se lie à la cellulose cristalline et à la paroi des plantes. L'application de CBEL au tabac induit des réponses de défense, une nécrose localisée, et protège la plante contre l'infection par Ppn. Au cours de ce travail, nous avons mis en évidence la présence de protéines homologues de CBEL chez plusieurs espèces du genre Phytophthora, et montré que cette molécule induit la défense chez plusieurs espèces végétales. Ces résultats classent CBEL parmi les éliciteurs généraux. Une caractérisation plus détaillée de l'activité élicitrice a été entreprise chez Arabidopsis thaliana. L'infiltration par CBEL de feuilles de plantes d'A. Thaliana d'écotype Col-0 induit des nécroses, la production d'éthylène, l'accumulation de glycoprotéines riches en hydroxyproline (HRGPs), d'activité peroxydasique, et l'expression des gènes de défense ASA1, PR-1, Wak1 et ACO1. Par l'utilisation de mutants affectés de perception de l'acide jasmonique (coi1) ou de l'éthylène (ein2), et de plantes affectées dans l'accumulation de l'acide salicylique (exprimant NahG), nous avons constaté que l'induction de nécrose est dépendante de l'acide jasmonique et de l'éthylène, tandis que l'accumulation d'HRGPs, d'activité peroxydasique ainsi que l'induction de Wak1 et PR-1 sont dépendantes de l'acide salicylique. Nos résultats suggèrent que CBEL active les trois voies de signalisation impliquées dans l'induction des défenses chez A. Thaliana. Ils montrent également que l'infiltration par CBEL de feuilles de plantes Col-0 les protège partiellement contre une infection par Colletotrichum destructivum. Afin d'évaluer la capacité de CBEL à conférer une protection contre des agents pathogènes lorsqu'elle est produite de façon endogène, des plantes transgéniques de tabac et d'A. Thaliana exprimant CBEL ont été générées. . . .

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12

Jaulneau, Valérie. "Caractérisation moléculaire d'un extrait d'algues vertes, stimulateur des défenses des plantes contre les agents pathogènes." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/2603/.

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La capacité des plantes à se défendre contre les parasites dépend de la perception d'éliciteurs qui induisent les défenses des plantes. Afin de les utiliser comme méthode alternative pour contrôler les maladies, il est nécessite d'identifier des sources abondantes et de caractériser leur activité. Au cours de ce travail, nous avons identifié un nouveau polysaccharide extrait d'algue verte, Ulva spp. , et caractérisé son activité biologique. Les molécules présentes dans l'extrait ont été séparées par leur poids moléculaire (PM). Seule la fraction de haut PM, qui contient essentiellement un polysaccharide sulfaté appelé ulvane, possède une activité. Les effets des ulvanes sur le transcriptome de M. Truncatula ont été comparés à ceux du méthyl jasmonate (MeJA) et de l'acibenzolar-S-methyl. La signature transcriptomique obtenue en réponse aux ulvanes présente de nombreuses similitudes à celle obtenue en réponse au MeJA. Ces deux traitements induisent des réponses régulées par la voie du JA telle que l'activation des inhibiteurs de protéases. L'expression de gènes dépendants cette voie est aussi induite chez A. Thaliana en réponse aux ulvanes. Enfin, les ulvanes entraînent une inhibition de la croissance in-vitro, qui est partiellement affectée chez le mutant PEPR2. L'efficacité protectrice de l'extrait brut a été testée contre divers parasites. Ainsi, il protège contre les oomycetes et les champignons responsables, respectivement, d'oïdium et de mildiou. Nos résultats montrent que les ulvanes induisent les défenses des plantes via la voie du JA et soulignent l'intérêt des outils d'analyse transcriptomique pour identifier de nouveaux éliciteurs capables de protéger les plantes The ability of plants to defend themselves against pathogens depends on the perception of elicitors, which induce plant defence. They might be considered as alternative tools for disease control in agronomic crops. Their industrial use needs to identify abundant sources and characterize their activity. Here we report on the identification of a new polysaccharide purified from the green algae Ulva spp. And the characterization of it biological activity in plants. Molecules contained in the extract were sized-fractionated. Analyses of the fractions revealed that biological activity was present only in the fraction of high molecular weight which contained most exclusively a sulfated polysaccharide named ulvan. Response to ulvan were compared to those induced upon methyl jasmonate (MeJA) and acibenzolar-S-methyl on the legume M. Truncatula using microarrays. Interestingly, ulvan gene expression signature showed significant similarity to MeJA and typical responses controlled by the JA pathway, such as induction of protease inhibitor activity. Expression of JA responsive genes, like PDF1. 2, was also induced in A. Thaliana after ulvan treatment. Ulvan provoked an inhibition of in-vitro growth, which was partially impaired in the mutant PEPR2. The efficient protection induced by the crude extract was tested against pathogens on various crops. So, it protect well against oomycetes and fungus that respectively cause downy and powdery mildews. Our results show that ulvan induces plant defences through the jasmonate signalling pathway and highlight the use of functional genomics to develop new bioactive compounds for plant protection

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13

Chambard, Marie. "Analyse génomique de l'ADN extracellulaire du Root Extracellular Trap (RET) et caractérisations omiques des "root Associated Cap-Devrived Cells" (AC-DC) chez le soja Glycine max (L.) Merr.1917." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR020.

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Le soja, culture d’intérêt agronomique mondiale et bientôt Normande, doit faire face à l’attaque de nombreux phytopathogènes et notamment à l’oomycète Phytophthora sojae Kaufm. & Gerd., qui engendrent chaque année d’importantes pertes économiques. Le RET (Root Extracellular Trap) est situé à l’apex racinaire, est constitué de cellules détachées de la racine appelées cellules frontières ou AC-DC (root Associated Cap-Derived Cells) et de leur mucilage associé. On retrouve au sein de ce mucilage des glycomolécules, des protéines, ou encore de l’ADN extracellulaire (ADNex). Cet ensemble, formant un territoire racinaire particulier, va permettre la protection de la racine et notamment de son apex contre les stress biotiques et abiotiques. Afin de mieux comprendre les mécanismes de défense racinaires, et notamment de certains acteurs du RET, une analyse transcriptomique et protéomique des AC-DC et de la racine et une analyse génomique de l’ADNex ont été réalisées en conditions témoin et élicitée avec PEP-13, un éliciteur provenant des oomycètes du genre Phytophthora sp. Les analyses transcriptomique et protéomique ont montré une spécificité des AC-DC par rapport aux racines et une réponse à PEP-13 qui semble différente entre ces deux zones. Le séquençage génomique de l’ADNex du RET a été réalisé afin de déterminer l’origine de celui-ci et savoir s'il existe une spécificité de séquences entre les deux conditions. Il semblerait que l'ADNex ait une meilleure couverture lors de l'alignement sur l’ADN mitochondrial et l’ADN plastidial comparé à l’ADN chromosomique. Cette différence de couverture peut indiquer une différence de persistance de l’ADNex dans le RET en fonction de son origine (chromosomique ou mitochondrial et plastidial), ou une libération dans le RET par ces organites. Il semblerait également qu’il n’y ait pas de différences entre les séquences d’ADNex du RET en condition élicitée avec PEP-13 ou témoin Soybean, a crop of Normand and world agronomic interest, is threatened by numerous phytopathogens like the oomycete Phytophthora sojae Kaufm. & Gerd., wich generate high levels of economical losses. The RET (root extracellular trap) is located at the root apex and is composed of border cells or AC-DC (root associated cap-derived cells) and their mucilage. This mucilage is made up of glycomolecules, proteins or also extracellular DNA (exDNA). The RET play a role in root protection against biotic stresses. In order to better understand the role of the RET in root protection, a transcriptomic and a proteomic analysis where done on AC-DC and roots in controle condition and in elicited condition with PEP-13 (an elicitor from Phytophthora sp.). The results show a specificity of AC-DC compared to the root, and an answer to PEP-13 wich seems to be different between these two tissues. An other experiment was to sequence RET exDNA in controle and elicited conditions, in order to define the origin of this exDNA. We show that the coverage of mitochondrial and plastidial DNA where much better than the coverage of chromosomic DNA. It could mean that chromosomic DNA isn’t conserved as well as organelles DNA, or exDNA could originate from organelles. Furthermore, results seems to show no differences between the sequences of elicited or control exDNA

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Nars, Amaury. "Caractérisation structurale et perception par la plante hôte Medicago truncatula des chitosaccharides pariétaux d'Aphanomyces euteiches, parasite de légumineuses." Phd thesis, Université Paul Sabatier - Toulouse III, 2013. http://tel.archives-ouvertes.fr/tel-00843419.

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Aphanomyces euteiches est un oomycète parasite racinaire des légumineuses causant des pertes de rendement récurrentes. La paroi d'A.euteiches contient 10% de N-acétylglucosamine (NAG) sous la forme de chitosaccharides non cristallins, associés aux glucanes pariétaux. Afin de pouvoir étudier leur activité biologique, un bioessai d'élicitation du système racinaire de la plante hôte Medicago truncatula a été mis au point en utilisant une préparation de fragments de chitine comme éliciteur témoin. La purification de fractions de parois hydrolysées, enrichies en NAG, a donné des fragments de glycanes composés de glucose et de NAG. Ces hétéropolymères présentent une structure nouvelle jamais décrite à ce jour. Le bioessai d'élicitation racinaire a révélé une activité biologique des fractions de paroi différente de celle des fragments de chitine chez M.truncatula. De façon intéressante, l'une des fractions induit des oscillations calciques nucléaires dans les cellules épidermiques de cultures de racines de M.truncatula, qui sont différentes de la réponse provoquée par des chitotétramères purs.

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15

Kim, Yonghyun. "Elucidation of the plant immune system by using the elicitor peptide PIP-1 as a chemical probe." Kyoto University, 2015. http://hdl.handle.net/2433/199359.

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Kyoto University (京都大学) 0048 新制・課程博士 博士(農学) 甲第19035号 農博第2113号 新制||農||1031(附属図書館) 学位論文||H27||N4917(農学部図書室) 31986 京都大学大学院農学研究科応用生命科学専攻 (主査)教授宮川恒, 教授西田律夫, 教授間藤徹 学位規則第4条第1項該当

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BRUNI, EMANUELE. "Multiple apoptotic pathways elicited by etoposide." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2013. http://hdl.handle.net/2108/202149.

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17

Gordon, Jean K. "Aphasic speech errors : spontaneous and elicited contexts." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36940.

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The goal of the current study was to investigate the retrieval of phonological word forms during the speech production of persons with aphasia, in order to inform models of the structure and function of the phonological lexicon. Using a naturalistic, connected speech task (picture description) and a more structured, single-word production task (picture naming) several characteristics of the target and its phonological 'neighbourhood' were examined, specifically: the target word's frequency of occurrence; the number of words which are phonologically similar to the target (neighbourhood density); and the average frequency of those 'neighbours' (neighbourhood frequency). To assess the influence of these factors on a target's susceptibility to error, the neighbourhood values of the words produced incorrectly in the picture description task were compared to those of a comparable corpus of correctly produced words from the same speech samples. In the naming task, target susceptibility was assessed by analyzing the error rates on individual stimulus items. The results of both tasks indicated that the lower a target's frequency of occurrence was, and the fewer neighbours it had, the more susceptible it was to error. To assess the impact of the neighbourhood on the outcome of the error, neighbourhood values of the errors produced were compared to those of their targets. In neither task were errors found to differ significantly from their targets in frequency or neighbourhood density. These results contribute to the literature on lexical access primarily by extending findings of neighbourhood effects in normal speech production to the aphasic population. In doing so, the present study lends support to the basic tenets of the Neighborhood Activation Model (Luce & Pisoni, 1998), and to the notion of the continuity thesis, in which aphasic deficits are hypothesized to reflect quantitative, rather than qualitative, differences from normal processing. Results are also in agreement with previous studies illustrating that aphasic error outcomes are strongly constrained by a number of linguistic factors which also constrain normal error production. Results are interpreted as consistent with an interactive connectionist framework of speech production.

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18

Geske, Elizabeth. "Audience frames elicited by televised political advertising." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1468083.

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19

Varela, Anna LÃdia Nunes. "AÃÃo de galactomanana sulfatada isolada de Adenanthera pavonina na resposta bioquÃmica de defesa do feijÃo-de-corda [Vigna unguiculata (L.) Walp.] desafiado pelo fungo Colletotrichum gloeosporioides." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13563.

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior O feijÃo caupi [Vigna unguiculata (L.) Walp.] Ã um alimento de grande importÃncia comercial, sendo a principal fonte alimentÃcia em algumas regiÃes, como no Nordeste brasileiro. Infelizmente, o feijÃo-de-corda estÃ sujeito ao ataque de vÃrios patÃgenos e pestes, acarretando perdas considerÃveis em sua produtividade. Para diminuir essas perdas, existem diversos mÃtodos quÃmicos que sÃo largamente utilizados, porÃm o uso indiscriminado de fungicidas tem causado danos ao meio ambiente e aos seres vivos. Na busca de alternativas ecologicamente saudÃveis, uma opÃÃo promissora seria a induÃÃo de mecanismos de defesa da prÃpria planta atravÃs de molÃculas elicitoras. Diante do exposto, o presente trabalho teve como objetivo elicitar respostas de defesa em feijÃo-de-corda atravÃs do uso de galactomanana sulfatada isolada de Adenanthera pavonina e induzir a resistÃncia ao fungo Colletotrichum gloeosporioides. Doze dias apÃs germinaÃÃo, plantas de feijÃo-de-corda (Vigna unguiculata) foram tratadas com galactomana de A. pavonina (nas concentraÃÃes de 100 mg/L e 200 mg/L), na ausÃncia ou presenÃa do fungo C. gloeosporioides (inoculado apÃs 6 h do tratamento com carboidrato) por 6, 12, 24 e 48 h, tendo sido realizadas as anÃlises bioquÃmicas nos extratos protÃicos obtidos das folhas primÃrias. Para as enzimas POX e APX ocorreu um significativo aumento a partir de 12 h do tratamento com a galactomanana. Em relaÃÃo a atividade das enzimas antifungicas βGLU e CHI, as plantas tratadas com a galactomanana, no geral, apresentaram um aumento acima de 50% em relaÃÃo ao controle. AnÃlises macroscÃpicas revelaram que as folhas tratadas com 200 mg/L da galactomanana e infectadas com o C. gloeosporioides apresentaram lesÃes necrÃticas visivelmente reduzidas em relaÃÃo ao controle. Ademais, a galactomana nÃo foi capaz de inibir a germinaÃÃo de esporos e crescimento vegetativo do fungo C. gloeosporioides in vitro. A partir dos resultados obtidos neste trabalho, conclui-se que, a galactomanana isolada de A. pavonina Ã capaz de aumentar a tolerÃncia da cultura de feijÃo-de-corda (V. unguiculata) contra o fungo C. gloeosporioides. Cowpea [Vigna unguiculata (L.) Walp.] is a food of great commercial importance, being the main food source in some regions such as northeastern Brazil. Unfortunately, cowpea is subject to attack by various pathogens and pests, causing considerable losses in productivity. To reduce these losses, there are several chemical methods that are widely used, but the indiscriminate use of fungicides has caused damage to the environment and living beings. In search of alternative environmentally friendly, a promising option would be the induction of defense mechanisms of the plant itself through elicitor molecules. Given the above, this study aimed to elicit defense responses in cowpea through the use of galactomannan isolated from Adenanthera pavonina and induce resistance to Colletotrichum gloeosporioides. Twelve days after germination, cowpea plants (Vigna unguiculata) were treated with A. pavonina galactomannan (at concentrations of 100 mg/L and 200 mg/L) in the absence or presence of the fungus C. gloeosporioides (inoculated 6 hours after treatment with carbohydrate) for 6, 12, 24 and 48 h were carried out on biochemical analysis of protein extracts obtained from primary leaves. For enzymes POX and APX a significant increase occurred after 12 h of treatment with the galactomannan. With respect to antifungal activity of the enzymes and βGLU CHI, the plants treated with the galactomannan in general, showed an increase above 50% compared to control. Macroscopic analysis revealed that the leaves treated with 200 mg/L of galactomannan and infected with C. gloeosporioides showed necrotic lesions visibly reduced compared to control. Furthermore, the galactomannan was unable to inhibit the germination of spores and vegetative growth of the fungus C. gloeosporioides in vitro. The results of the present study indicate that galactomannan isolated from A. pavonina can increase crop tolerance of cowpea (V. unguiculata) against the fungus C. gloeosporioides.

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20

Tse, Cheung-yin Sharon. "Cohesion in Cantonese-speaking children's picture-elicited narratives." Click to view the E-thesis via HKUTO, 1997. http://sunzi.lib.hku.hk/hkuto/record/B36209521.

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Thesis (B.Sc)--University of Hong Kong, 1997. "A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, April 30, 1997." Also available in print.

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21

Suga, Hiroaki 1963. "Catalytic antibodies elicited via homologous and heterologous immunization." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/17342.

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22

Varela, Anna Lídia Nunes. "Ação de galactomanana sulfatada isolada de Adenanthera pavonina na resposta bioquímica de defesa do feijão-de-corda [Vigna unguiculata (L.) Walp.] desafiado pelo fungo Colletotrichum gloeosporioides." reponame:Repositório Institucional da UFC, 2012. http://www.repositorio.ufc.br/handle/riufc/18856.

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VARELA, Anna Lídia Nunes. Ação de galactomanana sulfatada isolada de Adenanthera pavonina na resposta bioquímica de defesa do feijão-de-corda [Vigna unguiculata (L.) Walp.] desafiado pelo fungo Colletotrichum gloeosporioides. 2012. 96 f. Dissertação (Mestrado em Bioquímica)-Universidade Federal do Ceará, Fortaleza-CE, 2012. Submitted by Eric Santiago (erichhcl@gmail.com) on 2016-07-08T13:35:57Z No. of bitstreams: 1 2012_dis_alnvarela.pdf: 2177919 bytes, checksum: b7898740c28944706d715c2b6f0eb897 (MD5) Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-08-02T20:17:13Z (GMT) No. of bitstreams: 1 2012_dis_alnvarela.pdf: 2177919 bytes, checksum: b7898740c28944706d715c2b6f0eb897 (MD5) Made available in DSpace on 2016-08-02T20:17:13Z (GMT). No. of bitstreams: 1 2012_dis_alnvarela.pdf: 2177919 bytes, checksum: b7898740c28944706d715c2b6f0eb897 (MD5) Previous issue date: 2012 Cowpea [Vigna unguiculata (L.) Walp.] is a food of great commercial importance, being the main food source in some regions such as northeastern Brazil. Unfortunately, cowpea is subject to attack by various pathogens and pests, causing considerable losses in productivity. To reduce these losses, there are several chemical methods that are widely used, but the indiscriminate use of fungicides has caused damage to the environment and living beings. In search of alternative environmentally friendly, a promising option would be the induction of defense mechanisms of the plant itself through elicitor molecules. Given the above, this study aimed to elicit defense responses in cowpea through the use of galactomannan isolated from Adenanthera pavonina and induce resistance to Colletotrichum gloeosporioides. Twelve days after germination, cowpea plants (Vigna unguiculata) were treated with A. pavonina galactomannan (at concentrations of 100 mg/L and 200 mg/L) in the absence or presence of the fungus C. gloeosporioides (inoculated 6 hours after treatment with carbohydrate) for 6, 12, 24 and 48 h were carried out on biochemical analysis of protein extracts obtained from primary leaves. For enzymes POX and APX a significant increase occurred after 12 h of treatment with the galactomannan. With respect to antifungal activity of the enzymes and βGLU CHI, the plants treated with the galactomannan in general, showed an increase above 50% compared to control. Macroscopic analysis revealed that the leaves treated with 200 mg/L of galactomannan and infected with C. gloeosporioides showed necrotic lesions visibly reduced compared to control. Furthermore, the galactomannan was unable to inhibit the germination of spores and vegetative growth of the fungus C. gloeosporioides in vitro. The results of the present study indicate that galactomannan isolated from A. pavonina can increase crop tolerance of cowpea (V. unguiculata) against the fungus C. gloeosporioides. O feijão caupi [Vigna unguiculata (L.) Walp.] é um alimento de grande importância comercial, sendo a principal fonte alimentícia em algumas regiões, como no Nordeste brasileiro. Infelizmente, o feijão-de-corda está sujeito ao ataque de vários patógenos e pestes, acarretando perdas consideráveis em sua produtividade. Para diminuir essas perdas, existem diversos métodos químicos que são largamente utilizados, porém o uso indiscriminado de fungicidas tem causado danos ao meio ambiente e aos seres vivos. Na busca de alternativas ecologicamente saudáveis, uma opção promissora seria a indução de mecanismos de defesa da própria planta através de moléculas elicitoras. Diante do exposto, o presente trabalho teve como objetivo elicitar respostas de defesa em feijão-de-corda através do uso de galactomanana sulfatada isolada de Adenanthera pavonina e induzir a resistência ao fungo Colletotrichum gloeosporioides. Doze dias após germinação, plantas de feijão-de-corda (Vigna unguiculata) foram tratadas com galactomana de A. pavonina (nas concentrações de 100 mg/L e 200 mg/L), na ausência ou presença do fungo C. gloeosporioides (inoculado após 6 h do tratamento com carboidrato) por 6, 12, 24 e 48 h, tendo sido realizadas as análises bioquímicas nos extratos protéicos obtidos das folhas primárias. Para as enzimas POX e APX ocorreu um significativo aumento a partir de 12 h do tratamento com a galactomanana. Em relação a atividade das enzimas antifungicas βGLU e CHI, as plantas tratadas com a galactomanana, no geral, apresentaram um aumento acima de 50% em relação ao controle. Análises macroscópicas revelaram que as folhas tratadas com 200 mg/L da galactomanana e infectadas com o C. gloeosporioides apresentaram lesões necróticas visivelmente reduzidas em relação ao controle. Ademais, a galactomana não foi capaz de inibir a germinação de esporos e crescimento vegetativo do fungo C. gloeosporioides in vitro. A partir dos resultados obtidos neste trabalho, conclui-se que, a galactomanana isolada de A. pavonina é capaz de aumentar a tolerância da cultura de feijão-de-corda (V. unguiculata) contra o fungo C. gloeosporioides.

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23

Reynolds, Braden Beldon. "Development and Validation of a Portuguese Elicited Imitation Test." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8145.

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Elicited imitation (EI) is a method of assessing oral proficiency in which the examinee listens to a prompt and attempts to repeat it back exactly as it was heard. Research over recent decades has successfully established correlation between EI testing and other oral proficiency tests, such as the Oral Proficiency Interview (OPI) and the OPI by computer (OPIc). This paper details the history of oral proficiency assessment as well as that of EI. It then outlines the development process and validation of a Portuguese Elicited Imitation test. The processes of item selection and item validation are detailed followed by the criterion-related validation through a statistical correlation analysis of participants' results on an official American Council on the Teaching of Foreign Languages (ACTFL) OPIc and their predicted OPIc scores which were based on their results of the Portuguese EI calibration test. Results of the statistical analysis revealed a strong correlation between the predicted scores of the EI test and the actual OPIc scores. In order to go beyond previously completed EI research, this paper addresses the issue of face validity which has been a challenge for the proliferation of EI testing. Analysis of a survey administered after participants' completion of the two tests (OPIc and EI) addresses the experiences and reactions of the participants to the two testing formats. Suggestions for future use of EI as well as future research will be presented.

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Christensen, Carl V. "Fluency Features and Elicited Imitation as Oral Proficiency Measurement." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3114.

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The objective and automatic grading of oral language tests has been the subject of significant research in recent years. Several obstacles lie in the way of achieving this goal. Recent work has suggested a testing technique called elicited imitation (EI) can be used to accurately approximate global oral proficiency. This testing methodology, however, does not incorporate some fundamental aspects of language such as fluency. Other work has suggested another testing technique, simulated speech (SS), as a supplement to EI that can provide automated fluency metrics. In this work, I investigate a combination of fluency features extracted for SS testing and EI test scores to more accurately predict oral language proficiency. I also investigate the role of EI as an oral language test, and the optimal method of extracting fluency features from SS sound files. Results demonstrate the ability of EI and SS to more effectively predict hand-scored SS test item scores. I finally discuss implications of this work for future automated oral testing scenarios.

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Barrows, Jacob Garlin. "The Effect of Prompt Accent on Elicited Imitation Assessments in English as a Second Language." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5654.

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Elicited imitation (EI) assessment has been shown to have value as an inexpensive method for low-stakes tests (Cox & Davies, 2012), but little has been reported on the effect L2 accent has on test-takers' ability to understand and process the test items they hear. Furthermore, no study has investigated the effect of accent on EI test face validity. This study examined how the accent of input audio files affected EI test difficulty as well as test-takers' perceptions of such an effect. To investigate, self-reports of students' exposure to different varieties of English were obtained from a pre-assessment survey. A 63-item EI test was then administered in which English language learners in the United States listened to test items in three varieties of English: American English, Australian English, and British English. A post-assessment survey was then administered to gather information regarding perceived difficulty of accented prompts. A many facet Rasch analysis found that accent affected item difficulty in an EI test with a separation reliability coefficient of .98—British English being the most difficult and American English the easiest. Survey results indicated that students perceived this increase in difficulty, and ANOVAs between the survey and test results indicated that student perceptions of an increase in difficulty aligned with reality. Specifically, accents that students were “Not at all Familiar” with resulted in significantly lower EI test scores than accents with which the students were familiar. These findings suggest that prompt accent should be carefully considered in EI test development.

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Manly, Patricia Colleen. "The social impact of the response elicited by depressed behaviour." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29018.

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A fundamental assumption underlying any interpersonal model of depression is that depressed social behaviour evokes a predictable response from others that in turn contributes to depression. Whereas most recent research has focused on the response that the depressed elicit in others, the present study examined the social impact of that response. The central premise of interpersonal models of depression can be expressed more precisely in terms of interpersonal circumplex complementarity theory: The hostile-submissive quality that has been reported in depressed behaviour evokes a complementary response from others (labelled RD). That response, in turn, evokes more hostility and submissiveness in the depressed, thus perpetuating the cycle. To have clinical relevance, RD would also be expected to induce relatively negative mood. Predictions regarding possible intrapersonal mediating variables were derived from critics and proponents of cognitive models of depression. After initial mood was assessed, each of 12 0 female subjects was shown a videotape depicting either RD or a control condition. Each subject then completed questionnaires assessing mood, her perceptions of what she would be like in the company of the person she had watched, and the social impact of the person she had watched. It was predicted that, compared to the control group, a) subjects exposed to RD would show more negative mood, b) they would anticipate that they would be more hostile and submissive in the company of the person they saw, and c) RD would impact as the interpersonal complement of hostility-submission, whether according to the traditional model of interpersonal complementarity or a facet analytic approach. These three predictions were borne out and the facet analytic prediction was supported. Further predictions that preexisting depressive symptoms and cognitions would correlate with mood and social acceptance for experimental group subjects were not supported. Methodological and theoretical implications are discussed. Arts, Faculty of Psychology, Department of Graduate

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Schiopu, Nicolae. "Transient evoked otoacoustic emissions elicited by bone-conducted ultrasonic stimuli." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ29416.pdf.

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Dajas-Bailador, Federico. "Cellular responses elicited by stimulation of neuronal nicotinic acetylcholine receptors." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392053.

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Burdis, Jacob R. "Designing and Evaluating a Russian Elicited Imitation Test to Be Used at the Missionary Training Center." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4008.

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Elicited Imitation (EI) is an assessment approach that uses sentence imitation tasks to gauge the oral proficiency level of test takers. EI tests have been created for several of the world's languages, including English, Spanish, Japanese, French, and Mandarin. Little research has been conducted for using the EI approach with learners of Russian. This dissertation describes a multi-faceted study that was presented in two journal articles for the creation and analysis of a Russian EI test. The EI test was created for and tested with Russian-speaking missionaries and employees at the Missionary Training Center (MTC) in Provo, UT. The first article describes the creation of the test and analyzes its ability to predict oral language proficiency by comparing individuals' scores on the EI to their scores on the Oral Proficiency Interview (OPI). The test was found to effectively predict an individual's OPI score (R2 = .86). The second article analyzes the difference in person ability estimates and item difficulty measures between items from a general content bank and a religious content bank. The mean score for the content specific items (x̄ = .51) was significantly higher than the mean score for the general test (x̄ = .44, p < 0.001). Additionally, the item difficulties for the religious items were significantly less than the item difficulties for the general items (p < 0.05).

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Fong, Pun San. "The impact of favor-elicited feelings on reciprocity behavior across time /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?MARK%202006%20FONG.

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Dixon, Thomas Oliver. "An electrophysiological examination of visuomotor activity elicited by visual object affordances." Thesis, University of Plymouth, 2016. http://hdl.handle.net/10026.1/6758.

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A wide literature of predominantly behavioural experiments that use Stimulus Response Compatibility (SRC) have suggested that visual action information such as object affordance yields rapid and concurrent activation of visual and motor brain areas, but has rarely provided direct evidence for this proposition. This thesis examines some of the key claims from the affordance literature by applying electrophysiological measures to well established SRC procedures to determine the verities of the behavioural claims of rapid and automatic visuomotor activation evoked by viewing affording objects. The temporal sensitivity offered by the Lateralised Readiness Potential and by visual evoked potentials P1 and N1 made ideal candidates to assess the behavioural claims of rapid visuomotor activation by seen objects by examining the timecourse of neural activation elicited by viewing affording objects under various conditions. The experimental work in this thesis broadly confirms the claims of the behavioural literature however it also found a series of novel results that are not predicted by the behavioural literature due to limitations in reaction time measures. For example, while different classes of affordance have been shown to exert the same behavioural facilitation, electrophysiological measures reveal very different patterns of cortical activation for grip-type and lateralised affordances. These novel findings question the applicability of the label ‘visuomotor’ to grip-type affordance processing and suggest considerable revision to models of affordance. This thesis also offers a series of novel and surprising insights into the ability to dissociate afforded motor activity from behavioural output, into the relationship between affordance and early visual evoked potentials, and into affordance in the absence of the intention to act. Overall, this thesis provides detailed suggestions for considerable changes to current models of the neural activity underpinning object affordance.

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Tang, M. "Elicitor-induced defence response and signal mechanisms in Medicago sativa L." Thesis, Swansea University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639158.

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In this study, the responses and signal mechanisms were explored with a model system, concerning the interactions between lucerne suspension cells (Medicago sativa L., cv. Kabul) and elicitor either from avirulent (V2) or virulent (V1) isolate of Verticillium, alboatrum. V2 elicitor induced a two-phase of H2O2 accumulation in the cell cultures. Activation of defence expression led to an increase in PAL activity, phytoalexin accumulation and deposition of phenolic polymers. However, activities of antioxidant enzymes, such as catalase, peroxidases, glucanase, glutathione reductase, did not show obvious increase within 24 h after treatment with the elicitor. Glutathione S-transferase activity increased after 1st oxidative burst. V1 elicitor induced similar defence responses as V2 did, but a stronger response was observed when the same concentration of elicitor was used, confirming that Kabul is a resistance cultivar to V. albo-atrum. Ca2+ influx is necessary for oxidative burst, PAL activity and phytoalexin accumulation. Either blocking Ca2+ channel by La3+ or reduction of extracellular Ca2+ amount by EGTA, had an important inhibition on oxidative burst, PAL activity and phytoalexin accumulation. Intracellular Ca2+ also played a role in downstream signalling. Intracellular Ca2+ inhibitors. TBM-8 and Ruthenium red, strongly inhibited the PAL activity and phytoalexin accumulation. Oxidative burst has a relation with defence expression. An NADPH oxidase inhibitor, diphenyleneiodonium (DPI), which inhibited oxidative burst effectively, also inhibited PAL activity and phytoalexin accumulation. However, DCN, an inhibitor of peroxidase, also inhibited and oxidative burst, PAL activity and phytoalexin accumulated in micromolar range. Oxidative burst with superoxide-origin is related to defence activation. The H2O2 itself did not stimulate an activation of PAL activity. Addition of superoxide dismutase (SOD) stimulated an increase in H2O2 accumulation. Microsomal membranes are capable of superoxide synthesis when NADPH/NADH was used as electron donor, which was DPI-sensitive. This enzyme activity increased after treatment of the cell cultures with elicitor.

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Teigler, Jeffrey Edward. "Differential Innate Immune Stimulation Elicited by Adenovirus and Poxvirus Vaccine Vectors." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11279.

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Vaccines are one of the most effective advances in medical science and continue to be developed for applications against infectious diseases, cancers, and autoimmunity. A common strategy for vaccine construction is the use of viral vectors derived from various virus families, with Adenoviruses (Ad) and Poxviruses (Pox) being extensively used. Studies utilizing viral vectors have shown a broad variety of vaccine-elicited immune response phenotypes. However, innate immune stimulation elicited by viral vectors and its possible role in shaping these vaccine-elicited adaptive immune responses remains unclear. Here we show that Ad and Pox vectors display profound intra- and inter-group differences in innate immune cytokine and chemokine elicitation. The CD46-utilizing vectors Ad35, Ad26, and Ad48 induced greater anti-viral and proinflammatory cytokines and chemokines relative to Ad5 in vaccinated rhesus monkeys and stimulated human PBMC. Ad fiber protein, as well as other capsid components, influenced resultant Ad vector innate stimulatory phenotypes. Analysis of human sera from Ad26-vaccinated volunteers showed similar anti-viral and proinflammatory cytokine and chemokine elicitation. Mechanistic analysis of Ad innate immune stimulation showed greater amounts Ad35 and Ad26, and small amounts of Ad5, traffic to the late endosome following infection. Innate immune stimulation by all three was reduced by inhibition of endosomal acidification, Cathepsin B, and Caspase-1, suggesting a common set of innate immune sensors triggered by Ads between 0-6 hours post-infection, in agreement with trafficking data showing Ad vector colocalization in the late endosome at similar time points. These data suggest a model mechanism explaining differences in observed Ad vector innate immune stimulation phenotypes. Similar to results obtained with Ad vectors, analysis of innate cytokine and chemokine responses elicited by Pox vectors ALVAC, MVA, and NYVAC showed that all three were distinct, with the canarypox-based vector ALVAC eliciting a unique potent proinflammatory response. Together these results reveal surprising and pronounced differences in innate immune stimulatory properties of viral vectors. Furthermore, these results could lead to possible strategies for targeted construction of vaccines for desired innate immune phenotypes, and have profound implications on vaccine design against infectious diseases and cancers, as well as gene therapy.

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Almeida, Susana Cristina Aleixo de. "Emotional responses elicited by wine when pairing with high fat food." Master's thesis, ISA, 2017. http://hdl.handle.net/10400.5/14827.

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Mestrado em Viticultura e Enologia / Instituto Superior de Agronomia / Faculdade de Ciências. Universidade do Porto This work was aimed at the evaluation of emotional responses elicited by wine before and after food consumption. The tastings were performed by one trained panel and by consumers, segmented by gender, Vinotype, 6-n-propylthiouracil (PROP) sensitivity and Saliva flow rate. Three commercial red wines with different sensory features were used: i) Grand Gold awarded wine from Alentejo (2013); ii) wine from altitude vineyards in Douro (2011), iii) classical European old wine (1999) from Bairrada. Wines were evaluated using a tasting sheet with emotional and conventional tasting descriptors before and after eating a typical Portuguese dish, whose distinctive feature was its high fat content. Overall, food did not change the global evaluation scores given to the wines but some of their characteristics were scored significantly different through the emotional tasting. The results of both panels demonstrated that the emotional responses were more correlated with the global evaluation of the wines than the classical sensory descriptors. Within the trained individuals, the main correlations with global evaluation were obtained with “Initial Impression”, “Expectation for the mouth” and “Impression in relation to odor”. In particular, the global evaluation for the Bairrada wine, could be predicted by a model including these three variables with a R2=0.73. With the untrained tasters, the correlation with global evaluation was only significant for the “Impression in relation to odor”. The average scores given to the three wines by both panels did not diverge, despite their different sensory attributes. Therefore, our work only reflected trends in wine preferences. The untrained panel preferred the Alentejo wine while the trained panel preferred the Douro wine, before the food ingestion. The correlations between the global evaluation and the other sensory descriptors for the Alentejo wine could not explain this preference. We speculate that the untrained panel scored the wines based on what they are used to drink, giving lower scores to the unfamiliar one. The trained panel demonstrated a higher correlation between emotional and sensory descriptors. In fact, the trained panel seemed to understand better the different range of qualities of the wines. After ingesting food, the preference changed only for the trained panel, showing preference to the Bairrada wine. Both panels agreed that the old Bairrada was the most complex and difficult wine to understand In conclusion, the emotional tasting sheet was easy to interpret by all segments of consumers, leading to open and fair answers because it appeals to individual personal feelings. This tasting approach appears to be promising in the rapid learning of the different wine styles. In the future, it would be interesting to evaluate the evolution of scores given to unfamiliar wines that would require time to be appreciated using appropriate foods. This way, the classical European wines, that are difficult to understand by consumers, would have a better chance to be correctly appreciated N/A

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Moulton, Sara E. "Elicited Imitation Testing as a Measure of Oral Language Proficiency at the Missionary Training Center." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3137.

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This research study aimed to create an alternative method of measuring the language proficiency of English as a Second Language (ESL) missionaries at the Missionary Training Center (MTC). Elicited imitation (EI) testing was used as this measure of language proficiency and an instrument was designed and tested with 30 ESL missionaries at the MTC. Results from the EI test were compared with an existing Language Speaking Assessment (LSA) currently in use at the MTC. EI tests were rated by human raters and also by a computer utilizing automatic speech recognition technology. Scores were compared across instruments and across scoring types. The EI test correlated highly with the LSA using both scoring methods providing initial validity for future testing and use of the instrument in measuring language proficiency at the MTC.

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Son, Min Hye. "Examining Rater Bias in Elicited Imitation Scoring: Influence of Rater's L1 and L2 Background to the Ratings." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2263.

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Elicited Imitation (EI), which is a way of assessing language learners' speaking, has been used for years. Furthermore, there have been many studies done showing rater bias (variance in test ratings associated with a specific rater and attributable to the attributes of a test taker) in language assessment. In this project, I evaluated possible rater bias, focusing mostly on bias attributable to raters' and test takers' language backgrounds, as seen in EI ratings. I reviewed literature on test rater bias, participated in a study of language background and rater bias, and produced recommendations for reducing bias in EI administration. Also, based on possible rater bias effects discussed in the literature I reviewed and on results of the research study I participated in, I created a registration tool to collect raters' background information that might be helpful in evaluating and reducing rater bias in future EI testing. My project also involved producing a co-authored research paper. In that paper we found no bias effect based on rater first or second language background.

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Riedel, Helmut. "Analysis of early auditory evoked potentials elicited by stimuli with directional information." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965282740.

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Sá, Mário Moniz de. "Induction of phenylpropanoid metabolism in elicitor-treated hybrid poplar suspension-cultured cells." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30296.

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Induction of phenylpropanoid metabolism in many plants is associated with the induction of plant defence responses. Among these are the accumulation of phenylpropanoid-derived phytoalexins, increase in lignification around infected sites, and the accumulation of wall-bound phenolic compounds. I show in this work, that H11 hybrid cell suspension cultures when treated with either of three elicitors respond with an increase in phenylpropanoid metabolism. Activation proceeds rapidly from PAL and 4CL mRNA accumulation, to a massive increase in extractable PAL enzyme activity and finally there is accumulation of specific phenolic compounds in the cell extracts, culture filtrates, and cell walls. In addition, elicitor treatment causes cells to turn brown, indicative of phenolic compound accumulation. As in other plants, induction is dependent on culture age, is dose dependent, and the kinetics of induction is the same with all three elicitors. Based on the previously established mode of action of PGA lyase as an elicitor, it is concluded that in poplar, as in other plants, defence responses can be induced by elicitors from both fungal and plant cell wall origin. These results illustrate the successful use of plant suspension cultures as a simplified system to study inducible defence responses. In addition, and consistent with the ubiquitous nature of phenolics in poplar, phenylpropanoid metabolism may play an important role in plant defence responses in this species. Science, Faculty of Botany, Department of Graduate

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Kuhlmann, Georgiana L. (Georgiana Louise). "The 5' inositol phosphatase SHIP2 regulates EGF-elicited protrusion in MTLn3 cells." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/58294.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Biology, 2010. Cataloged from PDF version of thesis. Includes bibliographical references (p. 47-57). In metastatic cancer, cells must be able to migrate from their original environment, move through the blood or lymphatic system, and colonize a distant organ. Mena, a member of the Ena/VASP family of proteins, is upregulated in invasive populations of breast cancer cells. The Ena/VASP (enabled/vasodilator-stimulated phosphoprotein) family of proteins regulate both the geometry and dynamics of actin filament networks. Mena specifically is alternatively spliced with an invasive isoform, MenaINV, upregulated in metastastic cells, while an epithelial isoform, Menalla, is downregulated. SH2- domain containing 5-inositol phosphatase (SHIP2) interacts with Mena and is thought to play a role in breast cancer. SHIP2 is a 5-phosphatase that catalyzes the dephosphorylation of phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P 3) to phosphatidylinositol 3,4-bisphosphate (PI(3,4)P2) as well as the dephosphorylation of phosphatidylinositol 4,5- bisphosphate (PI(4,5)P 2). PI(3,4,5)P 3 and P][(4,5)P 2 are two major phosphoinositides at the plasma membrane and regulate a variety of cellular functions, including receptor signaling, membrane-cytoskeleton interactions and clathrin-mediated endocytosis. Here I have looked at the effects of knocking down SHIP2 in the MTLn3 cell line, a metastatic rat breast carcinoma line. I found that when SHIP2 is knocked down in cells, there is an increase in membrane protrusion upon stimulation with EGF, and that recruitment of Mena to the leading edge is enhanced, implying that this increase in protrusion may be due to a change in Mena localization. by Georgiana L. Kuhlmann. S.M.

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Michels, Chesney Elroy. "Investigation the immunological response elicited to the gastrointestinal nematode pinworm (Syphacia obvelata)." Doctoral thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/9030.

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Includes bibliographical references. It is important to emphasize with the advance of biotechnology and increased global exchange of animals and animal products, the risks of introducing adventitious infections. Previous studies of specitic-pathogen-free mouse colonies have identified the presence of infectious agents in 10-35% of research institutions investigated. Prevalence was higher among non-SPF mice with pinworm reported in 70% of institutions housing rodents under these conditions. Pinworm, a gastrointestinal (GI) nematode is commonly found in laboratory animals. The direct transmission of the parasite by contaminated food, water and bedding result in their continual re-exposure to the host, making the control of pinworm in animal holdings quite difficult. Syphacia obvelata, mouse pinworm, has been shown to interfere with research goals in several experimental models. In this study, we show the consequence of a pinworm outbreak in a transgenic barrier facility and define the immune response elicited in BALB/c mice. Infection with S. obvelata induced a transient Th2-type immune response with elevated cytokine production and parasite-specific IgG1. In contrast, HALB/c mice, deficient for IL-13, lL-4/13 or IL-4Ra showed chronic disease with more than 100-fold higher parasite burden, increased IFN-y production, parasite-specific IgG2b and a default Th2 response. Notably, infected lL-4-/- BALB/c mice showed only slight elevated parasite burden compared to controls, suggesting that IL-13 plays the dominant role in the control of S. obvelata. Furthermore, no significant eosinophilia, mastocytosis or goblet cell hyperplasia was induced. In a well-established ovalbumin (Ova) anaphylaxis model, we show that mice infected with S. obvelata induce a more severe anaphylactic reaction, with consistently greater temperature decline than their non-infected counterparts. Analysis of spleen cells further revealed a marked reduction of Ova-specific Th2 cytokines, highlighting the importance of pinworm free experimental mice. Finally, we generated anti-S. obvelata antibody to optimize the detection ELISA and identified target epitopes for future analysis. In conclusion, we identify the T helper immune response induced to S. obvelata and demonstrate the importance of IL-13 for the expulsion of the GI nematode. We show that S. obvelata induces a non-protective immune response to a common food allergen and confirm that the pinworm-specific ELISA is an effective diagnostic tool for detecting pinworm infected mice.

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Provine, Nicholas Mcdermott. "CD4 T Cells Regulate Adenovirus Vector-Elicited Cellular and Humoral Immune Responses." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:26718733.

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The processes that regulate viral vector vaccine-elicited cellular and humoral immune responses remain poorly defined. Thus, in this thesis, the role of CD4+ T cells – master regulators of adaptive immunity – in modulating adenovirus (Ad) vector-elicited cytotoxic CD8+ T cell responses and transgene-specific antibody responses was investigated. CD4+ T cell help is critical for the induction of CD8+ T cell and antibody responses, but the mechanisms and timing of help to each of these two arms of the immune system are distinct. CD4+ T cell help is required immediately and continuously for one week to drive functional CD8+ T cell effector differentiation and prevent dysfunction. Elevated signaling via PD-1, decreased IL-2 signaling, and increased non-canonical NFAT signaling all appear important for driving this CD8+ T cell dysfunction and impairing effector functionality. Absence of CD4+ T cells at the time of Ad vector immunization prevents the development of antigen-specific antibody responses. However, if the CD4+ T cell population is allowed to recover then fully functional antigen-specific antibody responses develop without the re-administration of antigen. Thus, CD4+ T cell help is absolutely required for the development of antibody responses following Ad vector immunization, but, intriguingly, help can be provided at a time separate from initial antigen exposure. Collectively, CD4+ T cell help and the appropriate timing of this help are critical for the generation of optimal CD8+ T cell and antibody responses following Ad vector immunization. These data advance our understanding of how CD4+ T cells regulate Ad vector-elicited cellular and humoral immune responses, and may improve rational vaccine design. Medical Sciences

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Mussa, Huda Jamal. "Elicitor-induced destabilization of PvPRP1 mRNA and characterization of its encoded protein /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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Monteiro, André Antonio. "Blood flow change in human masseter muscle elicited by voluntary isometric contraction." Stockholm : Kongl. Carolinska Medico Chirurgiska Institutet, 1990. http://catalog.hathitrust.org/api/volumes/oclc/21700760.html.

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Vaine, Michael. "Antibody Responses Elicited by DNA Prime-Protein Boost HIV Vaccines: A Dissertation." eScholarship@UMMS, 2010. https://escholarship.umassmed.edu/gsbs_diss/462.

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The best known correlate of protection provided by vaccines is the presence of pathogen specific antibodies after immunization. However, against the Human Immunodeficiency Virus-1 (HIV-1) the mere presence of antibodies specific for the viral Envelope (Env) protein is not sufficient to provide protection. This necessitates in depth study of the humoral responses elicited during infection and by vaccination. While a significant amount of effort has been invested in studying the evolution of antibody responses to viral infection, only limited progress in understanding antibody responses elicited through vaccination has been made. In the studies described here, I attempt to rectify this deficiency by investigating how the quality of a humoral response is altered with the use of different immunization regimens, in particular a DNA prime-protein boost regimen, or with the use of different model HIV-1 Env gp120 immunogens. In a New Zealand White (NZW) rabbit model, we demonstrate that the broader neutralizing activity elicited with the DNA prime-protein boost regimen may be the result of the elicitation of a higher avidity antibody response and a unique profile of antibody specificities. Specifically, use of a DNA prime-protein boost regimen elicits antibodies targeted to the CD4 binding domain of the HIV-1 Env, a specificity that was not frequently observed when only protein based immunizations were administered. We extended this analysis to sera from healthy human volunteers who participated in early phase HIV vaccine trials utilizing either a protein alone immunization regimen, a canarypox prime-protein boost immunization regimen, or a DNA prime-protein boost immunization regimen. Evaluation of sera from these trials demonstrated that the use of a DNA prime-protein boost regimen results in an antibody response with greater neutralization breadth characterized by an increased frequency and titer of antibodies targeted toward the CD4 binding site (CD4bs). In addition to this, the antibody response elicited by the DNA prime-protein boost regimen also exhibited the capability to mediate antibody dependent cell-mediated cytotoxicity (ADCC) activity as well as activation of the complement system. Additionally, in an attempt to better understand the capabilities of antibodies elicited by a DNA prime-protein boost regimen, we generated gp120 specific monoclonal antibodies (mAbs) from a single DNA primed-protein boosted NZW rabbit. Analysis of mAbs produced from this animal revealed that use of this immunization regimen elicits an antibody repertoire with diverse epitope specificity and cross reactivity. Furthermore, these select mAbs are capable of neutralizing heterologous HIV isolates. Further application of mAb generation in rabbits may provide a valuable tool to study immunogenicity of different vaccines and immunization regimens. Concurrently, while demonstrating that a DNA prime-protein boost regimen elicits a higher quality antibody response than that observed with other leading techniques, we also demonstrated that immunogen selection can play a vital role in the quality of the resulting antibody response. By immunizing with two closely related but phenotypically distinct model gp120 immunogens, known as B33 and LN40, we demonstrated that disparate gp120s have different intrinsic abilities to raise a heterologous neutralizing antibody response. Additionally, we showed that residues found within and flanking the b12 and CD4 binding sites play critical roles in modulating neutralizing activity of sera from animals immunized with LN40 gp120, indicating that the broader neutralizing activity seen with this immunogen may be due to differential elicitation of antibodies to this domain.

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Tsuchiya, Shinsuke. "Elicited Imitation and Automated Speech Recognition: Evaluating Differences among Learners of Japanese." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2782.

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This study addresses the usefulness of elicited imitation (EI) and automated speech recognition (ASR) as a tool for second language acquisition (SLA) research by evaluating differences among learners of Japanese. The findings indicate that the EI and ASR grading system used in this study was able to differentiate between beginning- and advanced-level learners as well as instructed and self-instructed learners. No significant difference was found between self-instructed learners with and without post-mission instruction. The procedure, reliability and validity of the ASR-based computerized EI are discussed. Results and discussion will provide insights regarding different types of second language (L2) development, the effects of instruction, implications for teaching, as well as limitations of the EI and ASR grading system.

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Pierce, Dana Lynn. "Mismatch Negativity Event Related Potential Elicited by Speech Stimuli in Geriatric Patients." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7487.

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Hearing loss, as a result of old age, has been linked to a decline in speech perception despite the use of additional listening devices. Even though the relationship between hearing loss and decreased speech perception has been well established, research in this area has often focused on the behavioral aspects of language and not on the functionality of the brain itself. In the present study, the mismatch negativity, an event related potential, was examined in order to determine the differences in speech perception between young adult participants, geriatric normal hearing participants, and geriatric hearing-impaired participants. It was hypothesized that a significantly weaker mismatch negativity would occur in the geriatric hearing-impaired participants when compared to the young adult participants and the geriatric normal hearing participants. A passive same/different discrimination task was administered to 10 young adult controls (5 male, 5 female) and eight older adult participants with and without hearing loss (4 male, 4 female). Data from behavioral responses and event related potentials were recorded from 64 electrodes placed across the scalp. Results demonstrated that the mismatch negativity occurred at various amplitudes across all participants tested; however, an increased latency in the presence of the mismatch negativity was noted for the geriatric normal hearing and the geriatric hearing-impaired participants. Dipoles reconstructed from temporal event related potential data were located in the cortical areas known to be instrumental in auditory and language processing for the young adult participants; however, within the geriatric normal hearing and the geriatric hearing-impaired participants, dipoles were seen in multiple locations not directly associated with language and auditory processing. Although not conclusive, it appears that within the geriatric normal hearing and the geriatric hearing-impaired participants there is slower processing of the speech information, as well as some cognitive confusion which leads to fewer available resources for interpretation.

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Abd, Rahim Muhamad Hafiz. "Production of Lovastatin, (+)-Geodin and Sulochrin by Aspergillus Terreus ATCC 20542 using Pure and Crude Glycerol." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/13792.

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This study aimed to characterise the production of lovastatin and its co-metabolites, sulochrin and (+)-geodin by A. terreus. Firstly, the study revealed that the types of carbon source influence lovastatin production, whilst the types of nitrogen source influence (+)-geodin and sulochrin production. Glycerol and yeast extract culture produced reasonable amount of lovastatin (25.68 mg/L), (+)-geodin (9.00 mg/L) and sulochrin (22.35 mg/L). This culture also produced pellets with hairy morphology, which is optimal for metabolite production. Secondly, the potential of crude glycerol (CG) as the substrate for A. terreus cultivation was investigated. At 30 g/L CG, (+)-geodin (13.14 mg/L) and sulochrin (14.79 mg/L) increased ~2-fold, but lovastatin production decreased by ~35%. The presence of saturated fatty acids (~48% reduction) and soap (~90% reduction) contributed to the inhibitory effect of CG on lovastatin production, with no effects on (+)-geodin and sulochrin production. Partial purification of CG using solvent and activated carbon resulted in an improved yield of all three metabolites. Thirdly, this study investigated the effects of selected ‘elicitors’ on the production of metabolites. Chemical elicitor was found to stimulate the production of lovastatin and sulochrin. (+)-geodin’s production was suppressed in high viscosity condition (<13 mg/L), whilst its production was stimulated by high shear force (>500 mg/L). These observations indicate that lovastatin and sulochrin may play a role in A. terreus’ defense mechanism. (+)-geodin, however, may be important for fungal pellet integrity or immediate response to injury, as physical elicition greatly enhanced its production. In conclusion, CG is a promising alternative substrate for metabolite production by A. terreus. This study, however, demonstrates no apparent relationship between the production of lovastatin, (+)-geodin and sulochrin by A. terreus.

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Carvalho, Paulo Roberto Santos [UNESP]. "Extratos vegetais: potencial elicitor de fitoalexinas e atividade antifúngica em antracnose do cajueiro." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/105258.

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Made available in DSpace on 2014-06-11T19:33:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-28Bitstream added on 2014-06-13T19:44:37Z : No. of bitstreams: 1 carvalho_prs_dr_jabo.pdf: 817782 bytes, checksum: f660ce8f19f225b54d401b2637051704 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Plantas e extratos vegetais podem apresentar ação antifúngica e de indução de defesa em função da presença de compostos com características elicitoras. Nesse sentido, foram objetivos do trabalho avaliar o efeito antifúngico dos extratos brutos aquosos de alecrim pimenta, nim e urtiga sobre Colletotrichum gloeosporioides; o potencial como elicitores de fitoalexina e o efeito de controle da antracnose em folhas destacadas de cajueiro. Os extratos brutos aquosos em três concentrações (5%, 10% e 15%) foram adicionados ao meio de cultura BDA para avaliar a ação sobre o crescimento micelial e esporulação e ao substrato Ágar-água para avaliar o efeito na germinação dos conídios e formação de apressórios. O potencial elicitor foi investigado em mesocótilos estiolados de sorgo e cotilédones de soja, determinando a capacidade elicitora das fitoalexinas deoxiantocianidina e gliceolina, respectivamente. Alecrim pimenta a 10% e 15% inibiu totalmente o crescimento micelial de C. gloeosporioides, a esporulação e germinação dos conídios. Nim inibiu parcialmente o crescimento micelial, esporulação e germinação dos conídios de forma proporcional à concentração usada. Urtiga estimulou o crescimento micelial, mas inibiu parcialmente a esporulação e a germinação. Apressórios não foram formados na presença dos três extratos brutos aquosos. Apenas alecrim pimenta a 15% mostrou potencial elicitor de deoxiantocianidina em sorgo. Já em soja foi observado potencial elicitor de gliceolina, embora com acentuada variação, tanto pelos três extratos brutos aquosos quanto pelas concentrações estudadas. O controle da antracnose em folhas destacadas de cajueiro foi observado em todas as concentrações dos extratos de alecrim pimenta e nim e, com urtiga a 15%. O maior efeito de controle foi proporcionado, igualmente, pelas concentrações do extrato de alecrim pimenta The use of plant extracts have shown antifungal and induction of defense due to the presence of compounds with characteristics elicitors. Therefore, the goals were to evaluate the antifungal effect of aqueous extracts of rosemary pepper, neem and nettle on Colletotrichum gloeosporioides and the potential as elicitors of phytoalexin and the effect of control of anthracnose in detached leaves of cashew plant. The extracts of three concentrations (5, 10 and 15%) were added to the culture medium to evaluate the effect on the mycelial growth and sporulation or to the water-agar substrate to evaluate the effect on conidial germination and apressoria formation. The potential elicitor was investigated in etiolated sorghum mesocotyl and soybean cotyledons, determining the ability of the phytoalexin elicitor deoxyanthocyanidin and gliceollin respectively. Rosemary Pepper 10 and 15% completely inhibited the mycelial growth of C. gloeosporioides and sporulation and germination. Nim partially inhibited the mycelial growth, sporulation and spore germination in proportion to the concentration used. Nettle stimulated mycelial growth, but partially inhibited the sporulation and germination. Appressoria were not formed in the presence of the three extracts. Only rosemary pepper 15% showed potential elicitor of deoxyanthocyanidin in sorghum. In soybean, potential elicitor of gliceolina, although with marked variation, was observed so the three extracts as the concentration. Control of anthracnose in detached leaves of cashew plant was observed at all concentrations of extracts of rosemary pepper and neem and nettle to 15%. The biggest effect of control was provided equally by the concentrations of the extract of rosemary pepper

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Pomerleau-Blondin, François. "Neural correlates of priming elicited by similar but perceptually different complex visual scenes." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82408.

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Neuroimaging studies on visual priming have reported decreased activity in extrastriate and inferior prefrontal cortices for the second presentation of an object. This effect is also observed for alternative exemplars of the initially presented object (e.g. two different pencils). An unanswered question is whether this decrease in activity can be found for the successive presentation of similar complex visual scenes. We used a test in which landscape pictures were divided vertically into three segments. A first segment was presented and followed several stimuli later by a second segment. Reaction time was faster for the second segment than for the first one. The presentation of the second segment was associated with reduced activity in late stage visual processing areas, which replicates and extends the results on priming of different exemplars of objects, and with increased activity mainly in frontal and parietal regions, which are known to be associated with memory retrieval.

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Bilovich, Avri. "Beyond introspection : an exploration of the correspondence between directly and indirectly elicited preferences." Thesis, University of Warwick, 2018. http://wrap.warwick.ac.uk/106381/.

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This thesis aims to explore the limits of introspection, concentrating on the methodological aspect of preference elicitation. I use the comparison between direct and indirect elicitation methods, as well as their use in predicting choices, to explore when people are able to self-report their preferences. Three distinct contexts are used: the purchasing of habitual grocery products, the preferences of ethical consumers, and the political preferences of urban Pakistanis towards the USA. The unreliability of direct elicitation methods, and the superiority of indirect methods in predicting choices that are uncovered in the first study are echoed in the context of ethical consumers. Indeed, even these more deliberative consumers, who reported an increased preference for ethical attributes, are shown to not be able to correctly report the drivers of their decisions. Conversely, the results of the third study indicated that urban Pakistani’s preferences towards the USA were introspectively accessible: both types of elicitation methods were aligned in their results and were robust to short term attempts to change them. This thesis contributes to the debate on the limits of introspection in several ways. Firstly, I demonstrate the inaccessibility of preferences for often experienced and purchased goods, even for more deliberative and attribute-conscious shoppers such as ethical consumers. I also demonstrate that unlike these preferences, political attitudes are more introspectively accessible. The work also presents a number of practical outcomes, such as the usability of lexicographic choice models with directly elicited preferences, as well as the plurality of ethical consumers’ concerns. Finally, the robustness of political attitudes in Pakistan to actual pro-American advertisements indicate the need for a change of strategy in promoting the USA’s positive impact in the country.

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