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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
731

Associations entre les apports en légumes et fruits et la présence d'altérations glycémiques chez les femmes avec un antécédent de diabète gestationnel

Mercier, Roxanne 24 April 2018 (has links)
Les femmes avec un antécédent de diabète gestationnel (DbG) sont plus à risque de diabète de type 2 (DbT2). Ainsi, certaines études se sont intéressées aux associations entre les apports alimentaires et le risque de DbT2 en période post-partum chez cette population. Par contre, à notre connaissance, aucune étude n’a évalué ces associations avec les apports en légumes et fruits (LF) chez ce groupe. Ainsi, l’objectif général de ce projet de maîtrise est d’évaluer l’association entre la consommation de LF et la présence d’altérations glycémiques chez les femmes avec un antécédent de DbG. Pour ce faire, les apports alimentaires en LF ont été évalués entre les femmes présentant ou non une altération glycémique et l’association entre les apports en LF, en légumes et en fruits et la présence d’altération glycémique a été établie. Les analyses ajustées pour l’âge et l’indice de masse corporelle (IMC) ont démontré que les femmes avec une altération glycémique avaient des apports inférieurs en LF et en légumes et non en fruits comparativement aux femmes sans altération glycémique. En considérant les mêmes cofacteurs, les résultats ont démontré que des apports supérieurs en LF et en légumes étaient associés à un risque inférieur d’avoir une altération glycémique, mais les résultats n’étaient pas significatifs pour les fruits. Bref, des apports supérieurs en LF sont associés à un risque inférieur de présenter une altération glycémique chez les femmes avec un antécédent de DbG. Ces résultats semblent davantage être associés aux apports en légumes. Ces analyses ajoutent à la littérature limitée chez cette population à risque et orientent vers des possibles pistes d’action afin de préciser les recommandations nutritionnelles en période post-partum. Des études d’intervention sur la prévention du DbT2 chez cette clientèle sont maintenant essentielles pour établir les liens de causalité et pour objectiver leurs effets à long terme. / Women with prior gestational diabetes mellitus (GDM) are at higher risk of type 2 diabetes (T2D). Therefore, some studies have investigated the association between dietary intake and the risk of T2D in the postpartum period in this population. However, to our knowledge, no studies have evaluated this association with fruit and vegetables (FV) intake in this group. Thus, the general objective of this master’s project is to evaluate the association between FV intake and the presence of glycemic alterations in women with prior GDM. For this purpose, dietary FV intake were assessed in women with and without glycemic alterations and the association between FV, vegetables and fruit intake and the presence of glycemic alterations was evaluated. Adjusted analyses for age and body mass index (BMI) demonstrated that women with glycemic alterations had lower FV and vegetables intake, but not fruit intake compared to women without glycemic alterations. Considering the same cofactors, the results demonstrated that higher intake of FV and vegetables were associated with a lower risk of having glycemic alterations, but the results were not significant for fruits. In summary, higher intake of FV are associated with a lower risk of having glycemic alterations in women with prior GDM. These results appear to be more associated with vegetables intake. Theses analyses add to the limited literature in this higher risk population and possibly help to clarify the nutritional recommendations in the postpartum period. Interventional studies on T2D prevention in this group are now essential to establish a causal relationship and to objectify long-term effects.
732

Variation du coût des fruits et légumes dans divers milieux de la grande région de Québec

Drouin, Sarah 16 April 2018 (has links)
Le groupe alimentaire des légumes et fruits en est un dont les bénéfices sur la santé ont été largement reconnus notamment en diminuant les risques de maladies chroniques telles que l'obésité, le diabète et certains cancers. Malgré les recommandations, un nombre considérable de Canadiens et Québécois n' atteignent pas le nombre minimal de portions recommandé par le Guide alimentaire canadien, spécialement les populations à faible revenu. L'accès économique aux aliments, en particulier la capacité à payer pour des aliments recommandés, est un déterminant important de la saine alimentation chez les ménages à faible revenu et compterait parmi les causes des inégalités sociales de santé. Cette étude exploratoire s'est intéressée à la variation du coût des fruits et légumes dans différents milieux socio-économiques de la région de Québec. Deux constats ressortent: (1) le coût d'un panier de fruits et légumes varie selon les types d' établissement (grande surface, surface conventionnelle, petite surface, fruiterie, dépanneur), mais non avec le niveau d'urbanisation (urbain; rural) ni la défavorisation matérielle et (2) tous les types d' établissement à l'étude sont plus nombreux par 100 km² dans le milieu urbain par rapport au milieu rural. D'autres études, couvrant un plus grand territoire et incorporant les aspects de l'environnement alimentaire sont nécessaires afin de conclure sur l' effet de l' accès économique aux fruits et légumes sur les inégalités de santé dans la région. Des actions et solutions pourraient être ainsi initiées afin d' éviter que des écarts de santé, s'ils existent, ne s'accentuent.
733

Étude de l'effet de la consommation d'un jus enrichi en fibres alimentaires sur la satiété et la réponse glycémique

Paquin, Julie 13 April 2018 (has links)
Le but de ce projet était d'étudier l'influence de jus enrichis en polysaccharides et dont la viscosité est contrôlée sur la réponse glycémique et la satiété chez l'humain. Des polysaccharides ont été sélectionnés sur la base des critères suivants: stabilité après traitement thermique, viscosité permettant l'acceptabilité du produit, viscosité reliée à l'impact sur la réponse glycémique dans la littérature (0,1 et 1,0 Pa.s à 30s"1 ) et évaluation organoleptique par un panel de dégustation. Un jus témoin sans polysaccharide a été élaboré; les trois autres formulations de jus ont été enrichies : de gomme xanthane, du P-glucane ou d'un mélange de gomme xanthane et de P-glucane. La consommation du jus enrichi du mélange de gomme xanthane et de P-glucane a résulté en une atténuation significative de la réponse glycémique de 0.8 mmol/L (P=0.001) et une augmentation significative de la sensation de satiété. Ces résultats s'expliquent par des viscosités élevées et un comportement rhéologique moins pseudoplastique que la gomme xanthane utilisée seule. L'importance d'utiliser la viscosité au lieu de la concentration en polysaccharide lors de l'élaboration d'aliments dans le but d'obtenir un impact sur la réponse glycémique, insulinémique et sur la satiété a été démontrée. / This project aims to study the impact on glycemic response and satiety of polysaccharide enriched juices having controlled viscosity. Polysaccharides were selected base on their thermal stability, viscosity as related in literature to the impact on glycemia (0.1 et 1.0 Pa.s at 30s"1 ) and sensory analysis. A control juice was developed and three other juices were enriched with either: xanthan gum, P-glucan or a mix of xanthan gum and P-glucan. The juice supplemented with the mix of xanthan gum and P-glucan demonstrated a significant attenuation of the glycemic response by 0.8mmol/L (P=0.001) and a positive impact on satiety. These results were related to the high viscosity of the juice and probably to the fact that this formulation was less pseudoplastic than the juice enriched with xanthan gum alone. These results showed the importance of using measured viscosity instead of polysaccharide concentration to impact on the glycemic, insulinemic response and satiety with fiber enriched food.
734

Le moment de la naissance du revenu imposable en droit fiscal belge: Fait générateur du revenu, interaction avec le régime des fruits civils, interaction avec le principe d'annualité de l'impôt

Henneaux, François 26 April 2021 (has links) (PDF)
Le moment où le revenu imposable naît a une incidence directe sur le moment où le contribuable est amené à payer l’impôt. En effet, pour prendre l’exemple des revenus d’activités, le contribuable paie l’impôt à un moment différent selon que le revenu imposable naît au moment de la naissance de la créance de revenu, au moment de l’exécution de la contre-prestation, au moment de l’exigibilité de la créance de revenu ou au moment du paiement de la créance de revenu. Pourtant, malgré son intérêt théorique et pratique, le sujet a peu été étudié jusqu’ici en droit fiscal belge. Cette thèse de doctorat entend contribuer à combler ce vide. La première partie identifie quels sont les faits générateurs du revenu en droit fiscal belge, en délimite les champs d’application respectifs et en précise les contours. Elle examine ainsi tour à tour le fait présumant la naissance du revenu, le fait générateur comptable, le fait générateur de la mise à disposition du revenu et les cas de « réalisation systématique » où le revenu naît de manière anticipée en raison de la perte pour le fisc du pouvoir d’imposer le revenu. La deuxième partie clarifie l’interaction entre les deux principaux faits générateurs du revenu ainsi identifiés – le fait générateur comptable et le fait générateur de la mise à disposition du revenu – et le régime des fruits civils. Dans son premier volet, elle détermine le fait générateur du fruit civil, cette question étant elle-même obscure, et précise la relation entre ce fait générateur et les principaux faits générateurs du revenu. Dans son second volet, elle clarifie la relation en droit civil et en droit fiscal entre, d’une part, la question de la naissance du revenu consistant en un fruit civil et, d’autre part, celle de la répartition de pareil revenu et de la détermination de la personne qui en est le contribuable. La troisième partie étudie le principe d’annualité de l’impôt contenu dans le Code des impôts sur les revenus 1992 en vertu duquel l’impôt est établi sur les revenus nés pendant la période imposable en raison de la survenance de leur fait générateur. Dans son premier volet, elle examine l’incidence de l’événement postérieur à la période imposable sur les revenus nés pendant cette période. Dans son second volet, elle établit un panorama des dérogations, explicites ou implicites, au principe d’annualité de l’impôt et puis analyse la plus complexe d’entre elles, à savoir celle relative aux loyers professionnels. Si la thèse examine principalement ces différentes questions de lege lata, elle ne délaisse pas pour autant tout aspect de lege ferenda. D’une part, sur la forme, elle formule plusieurs propositions d’amendements à droit constant pour améliorer la qualité de la loi. D’autre part, sur le fond, elle suggère d’autres solutions que celles du droit positif concernant les points qui méritent l’attention du législateur. / Doctorat en Sciences juridiques / info:eu-repo/semantics/nonPublished
735

A marketing plan for the export of citrus products to the People's Republic of China

Du Toit, Jacobus Stephan 12 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Bruce Sherr, commodities research expert, asked the question: "What are the three things that drive global agriculture today?" "China, China, China", he quoted in answering his own question. China has 1,2 billion people with tremendous purchasing power and has maintained an economical growth rate of more than 8% over the past five years. All indications are that this growth rate will be sustained in the immediate future. This naturally makes China an export market worth considering. The South African citrus industry underwent material changes during 1997, which lead to the deregulation of a single marketing structure from the 1st of January 1998 that previously forced citrus producers to deliver all their citrus for export to Outspan, now Capespan. This caught the majority of citrus producers off-guard, as they suddenly had to decide among numerous agents/buyers who joined the industry as role players. A few of the smaller citrus producers even embarked on the direct marketing of their citrus to cut out the "middle man" in an attempt to save costs and negotiate higher prices, with mixed results. It is generally believed that better prices can be achieved by embarking on a direct marketing strategy, but is the process really that simple? This study will investigate the possible exportation of citrus to the People's Republic of China (PRC) by analysing the Chinese market as citrus exports to China has yielded acceptable returns in the past and is certainly an export market to consider. The analysis of the Chinese market will be followed by the broad design of an export marketing plan for citrus to the PRC using a medium sized citrus export company as an example. In conclusion and as a summary certain important issues impacting specifically on the export of South African citrus to the PRC will be addressed and the findings on the viability of implementing an export strategy for citrus to the PRC recommended. / AFRIKAANSE OPSOMMING: Bruce Sherr, 'n kenner op die gebied van navorsing van kommoditeite het eendag die vraag gevra: "Watter drie dinge dryf die wêreldlandbou deesdae?" "China, China, China" het hy self sy vraag geantwoord. China beskik oor 1,2 biljoen inwoners met 'n ongelooflike koopkrag en handhaaf 'n ekonomiese groeikoers van meer as 8% per jaar oor die laaste 5 jaar. Alle aanduidings is dat hierdie groeikoers volhou sal word vir die afsienbare toekoms. Hierdie feite maak van China 'n vanselfsprekende mark om te oorweeg vir die uitvoer van produkte. Die Suid-Afrikaanse sitrusbedryf het geweldige veranderings ondervind gedurende 1997, wat gelei het tot die afskaffing van 'n een-kanaalbemarkingstruktuur vir sitrus vanaf 1 Januarie 1998, wat voorheen sitrusprodusente verplig het om alle sitrus vir die uitvoermark aan Outspan, nou Capespan, te lewer. Hierdie wysiging het die meeste sitrusprodusente onkant gevang wat skielik 'n keuse moes maak tussen die menigte agente/kopers wat tot die Suid-Afrikaanse sitrusbedryf toegetree het. Sommige van die kleiner sitrusprodusente het selfs hul hand aan direkte bemarking gewaag in 'n poging om die "middelman" uit te skakel in 'n poging om koste te bespaar en hoër pryse te beding, met gemengde welslae. Daar word algemeen geglo dat hoër pryse behaal sal kan word deur 'n direkte bemarkingstrategie te volg, maar is die proses werklik so eenvoudig? Hierdie studie sal die moontlike uitvoer van sitrus na die Peoples Republic of China (PRC) ondersoek deur die Chinese mark te analiseer, aangesien sitrusuitvoere na China in die verlede 'n aanvaarbare opbrengs gelewer het, wat dit sekerlik 'n uitvoermark maak om te oorweeg. Die analise van die Chinese mark sal opgevolg word deur die breë ontwerp van 'n uitvoerbemarkingsplan vir sitrus na die PRC deur 'n mediumgrootte sitrusuitvoermaatskappy te neem as voorbeeld. Ter afsluiting en opsomming sal sekere belangrike aspekte wat 'n invloed kan uitoefen op die uitvoer van Suid-Afrikaanse sitrus na die PRC aangespreek word en sal daar 'n finale bevinding gemaak word oor die lewensvatbaarheid van die implimentering van 'n uitvoerbemarkingstrategie vir sitrus na die PRC.
736

Behind the scenes of network marketing : A case study of Tahitian Noni International

Bråneryd, Camilla, Friberg, Tobias January 2008 (has links)
<p>More companies have become aware of the need to find new ways of marketing, and network marketing is an alternative that has had great success. The purpose of this thesis is to identify what measures are used within a network marketing company to encourage the product consultants (PCs) to expand their networks. This study was conducted by interviewing three PCs and the Swedish marketing manager of Tahitian Noni International (TNI). A model is presented to structure the empirical findings, which shows that it is mainly the bonus system that is the catalyst in the organization, but also the company’s educations are of importance.</p>
737

Les contrats inter-entreprises dans le commerce de produits périssables : le cas des exportations de fruits du Chili analysé avec la Théorie des Coûts de Transaction et l’Analyse Institutionnelle / Inter-firm contracts in the international perishable products trade : the case of Chilean fruit exports through the lens of Transaction Cost Economics and Institutional Analysis

Pavez, Iciar 10 July 2013 (has links)
Cette thèse examine les déterminants qui expliquent les types de contrats choisis par les exportateurs et les importateurs pour gérer les risques du commerce international. Elle analyse le cas des exportations chiliennes comme l'un des leaders de l'hémisphère sud sur le commerce des fruits. En appliquant la Théorie de Coûts de Transaction et l'Analyse Institutionnelle, ce travail étudie l'influence de l'incertitude environnementale et comportementale ainsi que la spécificité des actifs sur le degré de complétude, la formalisation et l'exécution des contrats. Cette recherche applique une méthodologie multistrand intégrant des méthodes qualitatives et quantitatives. L'analyse utilise les informations provenant de 39 entretiens directs avec des exportateurs et des importateurs et de 65 enquêtes auprès d' exportateurs conduites à l'aide d'un questionnaire. Elle s'appuie également sur une base de données exhaustive issue des douanes chiliennes et documentant les 170370 transactions avec leurs contrats respectifs réalisées par le Chili dans ses exportations vers l'ensemble du monde sur la période 2009-2010. Elle s'appuie enfin sur 44 cas d'arbitrage international dans le commerce de fruits et légumes. Les résultats montrent que les niveaux d'incertitude environnementale liés aux « risques - pays importateurs » conduisent à des contrats plus complets tandis que des niveaux d'incertitude liés à la périssabilité des fruits conduisent à des contrats moins complets. De son côté, la pénurie d'offre sur le marché met l'entreprise exportatrice dans une position favorable pour négocier des contrats plus complets. Ces transactions internationales sont supportées par des moyens oraux et écrits; dans le négoce international des fruits, les contrats signés sont plus importants que pressenti, et leur rôle est davantage destiné à satisfaire les exigences institutionnelles qu'à compenser les risques. Pour faire respecter les contrats, les entreprises adoptent des mécanismes formels comme les inspections, les assurances et l'arbitrage, ainsi que des mécanismes informels tels que la confiance et la réputation. Cette étude a ses limites car elle porte principalement sur le point de vue de l'exportateur, la base de données des douanes ne fournissant pas l'identité de l'importateur et l'analyse transversale ne permettant pas d'observer l'évolution des pratiques contractuelles dans la durée. Jusqu'à présent, peu de recherches empiriques ont été faites sur les contrats intégrés dans différents contextes institutionnels; cette thèse contribue donc à la connaissance des choix contractuels dans 117 pays importateurs et plus généralement à la compréhension du commerce international des produits périssables. Elle est sur le plan académique, une contribution à la littérature économique et gestionnaire des contrats (complétude, formalisation, exécution) et des changements de forme de gouvernance dans les filières internationales. / This doctoral dissertation examines the determinants explaining the type of contracts chosen by exporters and importers to manage the hazards of international trade. It analyzes the case of Chilean off-season exports as one of the southern-hemisphere leaders in the fruit trade. Applying Transaction Cost Economics and Institutional Analysis as a framework, this work will analyze the influence of environmental and behavioral uncertainty and time-specificity on the degree of completeness, formalization and enforcement of contracts. A multi-strand research design integrating qualitative-quantitative methods is applied to analyze information gathered through: 39 face-to-face interviews with exporters and importers; questionnaire surveys from 65 exporters; an exhaustive Chilean customs database containing 170,370 shipments and contracts from Chile to worldwide buyers; and 44 international arbitration cases for the fruit and vegetable trade. The results show that high levels of uncertainty in the alternative importing countries increase the use of more complete contracts. When levels of fruit perishability are high, this often leads to less complete contracts. Shortage of market supply allows the exporting company a favorable position to negotiate a more complete contract. International transactions are supported by oral and written means; the use of signed contracts is more important than perceived in the fruit industry, but its role is more oriented to respond to institutional requirements rather than as a mechanism to offset hazards, such as exporting to risky countries or dealing with distrustful importers. To enforce contracts firms adopt formal and informal mechanisms. These include inspections, insurance, arbitration, in addition to trust and reputation. Limitations of this study include: the customs database does not include the identity of the importer, the cross-sectional analysis performed does not allow observing the evolution of contracting practices, the study is placed predominately from the exporter's perspective. There is also little empirical research on contracts analyzing transactions embedded in different institutional settings. This thesis contributes to the knowledge of contractual choices in 117 importing countries. It contributes to the understanding of international trade of perishable products. It also contributes to the economics and management literature on international contract completeness, formalization, enforceability, and to literature focusing on the changes of governance in the international supply chains.
738

Composição fenólica e atividade biológica in vitro e in vivo de frutas nativas brasileiras / Phenolic composition and biological activity in vitro and in vivo of Brazilian native fruits

Soares, Jackeline Cintra 03 April 2018 (has links)
O Brasil possui condições climáticas adequadas para o desenvolvimento de um grande número de frutas nativas e essa biodiversidade tem se tornado um caminho promissor para a descoberta de novos compostos bioativos capazes de ser utilizados na formulação de alimentos funcionais e medicamentos. Os compostos fenólicos apresentam ações específicas, podendo atuar como antioxidantes e anti-inflamatórios, assim prevenindo doenças crônicas. Diante do exposto, o objetivo deste trabalho foi avaliar o potencial antioxidante, antiinflamatório e a composição fenólica de dez frutas nativas brasileiras ainda pouco conhecidas: araçá-boi (Eugenia stipitata), cambuití-cipó (Sagerectia elegans), murici vermelho (Bysonima arthropoda), murici guassú (Byrsonima lancifolia), morango silvestre (Rubus rosaefolius), cambuci (Campomanesia phaea), jaracatiá-mamão (Jacaratia spinosa), juquirioba (Solanum alterno-pinatum), fruta-do-sabiá (Acnistus arborescens) e cajá (Spondias mombin L.). Os extratos etanólicos (80% v/v) das polpas foram analisados inicialmente quanto à capacidade de sequestro dos radicais ABTS&#8729+ e ROO&#8729. A atividade anti-inflamatória foi avaliada in vivo por meio do modelo de migração de neutrófilos induzida por carragenina, enquanto que a composição fenólica foi realizada por técnicas cromatográficas (CLAE-DAD e CG-EM). As 5 frutas com as maiores atividades biológicas foram ainda analisadas quanto à capacidade de sequestro de O2 &#8729-, HOCl e NO&#8729, atividade anti-inflamatória por meio do ensaio de ativação do fator nuclear-&kappa;B (NF-&kappa;B) e composição fenólica por espectrometria de massas de alta resolução (LC-ESI-QTOF-MS). Em relação ao sequestro do radical ABTS&#8729+ o cambuití-cipó apresentou a maior atividade (749,88 &mu;mol TE.g-1) e para o ROO&#8729 o murici vermelho apresentou a maior atividade antioxidante (559,09 &mu;mol TE.g-1). Os animais tratados com araçá-boi, cambuití-cipó, murici vermelho, cajá e morango silvestre apresentaram reduções no influxo de neutrófilos comparados ao grupo carragenina (p < 0,05). Por meio das técnicas de CLAE-DAD e CG-EM foi possível identificar compostos fenólicos pertencentes a classe dos flavonoides (catequina, epicatequina, rutina, quercetina glicosilada, kaempeferol glicosilado, quercetina, procianidina B1 e procianidina B2), sub-classe do ácido hidroxibenzóico (ácido gálico) e sub-classe dos ácidos hidrocinâmicos (ácido cumárico, ácido ferúlico e caféico). O araçá-boi, cambuití-cipó, murici vermelho, morango silvestre e cajá foram as cinco frutas que apresentaram as maiores atividades antioxidantes e/ou anti-inflamatórias, cujo perfil fenólico por LC-ESI-QTOF-MS indicou a presença de 18 compostos no araçá-boi, 32 no cambuitícipó, 26 no murici vermelho e 20 e 11 compostos no morango silvestre e cajá, respectivamente. Vários dos compostos fenólicos identificados foram encontrados pela primeira vez nessas espécies. O cambuiti-cipó e murici vermelho se destacaram em relação ao sequestro de HOCl (EC50 4,99 e 4,41 &mu;g mL-1, respectivamente) e o cambuití-cipó foi o mais ativo para desativar o radical O2 &#8729- (EC50 68,33 &mu;g mL-1) e NO&#8729 (EC50 0,78 &mu;g mL-1). Já os extratos de murici-vermelho, cambuití-cipó e morango silvestre inibiram significativamente a ativação do NF-&kappa;B. Portanto, as frutas nativas brasileiras são fontes de substâncias antioxidantes e anti-inflamatórias, bem como de uma grande diversidade de compostos fenólicos, os quais podem propiciar importantes benefícios para a saúde humana. / Brazil has favorable climatic conditions for the development of a large number of native fruits and this biodiversity has become a promising path towards the discovery of new bioactive compounds capable of being used in the formulation of functional foods and medicines. Phenolic compounds show specific action mechanisms, being able to act as antioxidants and anti-inflammatories, thus preventing chronic diseases. However, few Brazilian native fruits are well known and consumed by the population, undermining the investigation of chemical composition as well as the identification/quantification of bioactive compounds. In light of this, the objective of this work was to evaluate the antioxidant and anti-inflammatory potentials as well as the phenolic composition of ten underexploited Brazilian native fruits, namely: araçá-boi (Eugenia stipitata), cambuití-cipó (Sagerectia elegans), murici vermelho (Bysonima arthropoda), murici guassu (Byrsonima lancifolia), morango silvestre (Rubus rosaefolius), cambuci (Campomanesia phaea), jaracatiá-mamão (Jacaratia spinosa), juquirioba (Solanum alterno-pinatum), fruto-do-sabiá (Acnistus arborescens) and cajá (Spondias mombin L.). Pulps ethanolic extracts (80%, v/v) were initially analyzed regarding scavenging capacity of the ABTS&#8729+ and ROO&#8729 radicals. Antiinflammatory activity was evaluated in vivo using the carrageenan-induced neutrophil migration model, while phenolic composition was determined by chromatographic techniques (HPLC-PAD and GC-MS). The five fruits with the highest biological activities were analyzed for O2&#8729-, HOCl and NO&#8729 radicals scavenging capacities, for in vitro anti-inflammatory activity by nuclear factor-&kappa;B (NF-&kappa;B) activation, and for phenolic composition by High Resolution Mass Spectrometry (LC-ESI-QTOF-MS). In relation to ABTS&#8729+ radical scavenging cambuiticipó showed the highest activity (749.88 &mu;mol TE.g-1), while for ROO&#8729 scavenging, murici vermelho had the highest antioxidant activity (559.09 &mu;mol TE.g-1). The animals treated with araçá-boi, cambuití-cipó, murici vermelho, cajá and morango silvestre reported decreases in neutrophils influx compared to carrageenan group (p <0.05). It was possible to identify by HPLC-DAD and GC-MS techniques phenolic compounds belonging to the class of flavonoids (catechin, epicatechin, rutin, glycosylated quercetin, glycosylated kaempeferol, quercetin, procyanidin B1 and procyanidin B2), subclass of hydroxybenzoic acid (gallic acid) and subclass of hydrocinnamic acids (coumaric, ferulic and caffeic acids). Araçá-boi, cambuitícipó, murici vermelho, morango silvestre and cajá were the five fruits with the highest antioxidant and / or anti-inflammatory activities. The phenolic profile analysis by LC-ESIQTOF- MS pointed the presence of 18 compounds in araçá-boi, 32 in cambuití-cipó, 26 in murici vermelho, 20 in morango silvestre and 11 in cajá. Several of the identified phenolic compounds were found for the first time in these fruit species. Cambuiti-cipó and murici vermelho stood out in relation to HOCl scavenging (EC50 4.99 and 4.41 &mu;g.mL-1, respectively) and cambuití-cipó was the most active to deactivate both O2 &#8729- radical (EC50 68.33 &mu;g.mL-1) as NO&#8729 (EC 500.78 &mu;g.mL-1). Murici vermelho, cambuití-cipó and morango silvestre extracts significantly inhibited the activation of NF- &kappa;B.Therefore, Brazilian native fruits are sources of antioxidant and anti-inflammatory substances, as well as a great diversity of phenolic compounds, which can provide important benefits for human health.
739

Transformação genética e patogenicidade de Guignardia citricarpa / Genetic transformation and pathogenicity of Guignardia citricarpa

Rodrigues, Maria Beatriz Calderan 23 August 2010 (has links)
O Brasil é líder absoluto no comércio internacional de suco de laranja concentrado congelado participando com 82% do volume comercializado no mundo. Guignardia citricarpa é um fungo Ascomiceto agente causal da Mancha Preta dos Citros (MPC), uma doença importante no contexto da Citricultura, causando lesões negras em frutos tornando-os impróprios para a exportação, já que não são aceitos na União Européia pois o patógeno é classificado como quarentenário. O presente trabalho teve como objetivo principal estabeler a metodologia de transformação genética de G. citricarpa para futuramente auxiliar no entendimento dos mecanismos de patogenicidade desta espécie, visando diminuir perdas na citricultura brasileira devido à MPC. Além disso, foi realizada uma análise do gene da enzima endopoligalacturonase, a qual está associada à capacidade de patógenos em colonizar plantas. Para elucidar esse fenômeno, foi realizada a busca de genes relacionados à patogenicidade em outros fungos fitopatogênicos previamente descritos e confirmados participarem no processo de doenças em diversas plantas. Considerando que esses genes possuem uma região conservada para esse fim, após o alinhamento dessas sequências foram construídos primers e o gene de endopoligalacturonase foi identificado no gênero Guignardia sp. Outra espécie pertencente a esse gênero é G. mangiferae, conhecida como endófito de citros, ou seja, coloniza os tecidos internos da planta hospedeira sem causar dano. Em análises enzimáticas foi observado que a quantidade de endopoligalacturonase produzida pela espécie patogênica é superior à da espécie endofítica, mostrando que essa enzima pode participar do processo de patogenicidade de G. citricarpa. Estudos para comprovar a participação de genes nos mecanismos de patogenicidade em diversas espécies utilizando reconhecimento de genes e genômica funcional, expressão e knockout de genes estão sendo realizados, permitindo uma visão geral da organização genômica do sistema patogênico. Pensando nisso, esse trabalho descreve pela primeira vez a metodologia de transformação genética de G. citricarpa via micélio e a obtenção de transformantes expressando a proteína verde fluorescente (GFP). Micélios do fungo foram transformados pelo sistema via Agrobacterium tumefaciens com o plasmídeo pFAT-gfp, contendo os genes de resistência à higromicina B (hgr) e da GFP. A otimização do protocolo de agrotransformação foi realizada a partir do teste de diferentes condições como: tipo de membrana, concentração de agente indutor e tempo de cocultivo. A melhor condição incluiu a utilização de membrana de éster de celulose; 200 PM de AS e 96 horas de co-cultivo. Os transformantes apresentaram alta estabilidade mitótica (82%) e tiveram a inserção do gene hgr confirmada por PCR e do gfp observada em microscopia óptica de epifluorescência. Além disso, foi acompanhado o desenvolvimento do fungo inoculado em frutos, mostrando a interação planta-patógeno. O estabelecimento do sistema de transformação por Agrobacterium para G. citricarpa possibilita o uso dessa ferramenta para estudos de mutagênese insercional e interrupção gênica visando a identificação de genes importantes, como os envolvidos com os mecanismos de patogenicidade utilizados por esse fungo. / Brazil is the world leader in the international trade of frozen orange juice concentrate, taking part with around 82% of the traded volume. Guignardia citricarpa (anamorph Phyllosticta citricarpa) is a fungal pathogen of citrus plants, being described as the causal agent of citrus black spot (CBS), one of the most important fungal diseases of citrus worldwide. Its symptoms are black lesions on fruit, making them unsuitable for the international fresh market, since they are included in the quarantine list of the European Plant Protection Organization (EPPO). Moreover, when the disease is severe it may cause extensive premature fruit drop that reduces yields of fruit for processing. Taking this into consideration, the current work aimed to improve the understanding on the pathogenic mechanisms of this fungus. Firstly, in an attempt to elucidate this phenomenon, it was performed a search for pathogenicity genes previously reported to some pathogenic fungi and confirmed to participate in the process of infection in many plants , especially endopolygalacturonase. Primers were designed using the conserved regions of the genes and allowed the identification of the Guignardia spp. endopolygalacturonase gene for the first time. This enzyme has been described as playing important role in the process of fungal diseases in plants. In the present work, enzymatic analysis showed that the pathogen G. citricarpa produced significantly greater amounts of endopolygalacturonase when compared to G. mangiferae, a closely related fungus described as a citrus endophyte. This result suggests that this enzyme may participate in the process of pathogenicity, characteristic of the pathogenic species. Genetic transformation methods have been used to prove the involvement of genes in pathogenic mechanisms, however, a suitable methodology for G. citricarpa has not been described yet. In this way, this study describes for the first time a methodology for genetic transformation of G. citricarpa via mycelia and the successful generation of transformants expressing the green fluorescent protein (GFP) and resistant to the hygromycin B antibiotic. Mycelia of the fungus were genetically transformed via Agrobacterium tumefaciens hosting the plasmid pFAT-gfp, which carries the genes for resistance to hygromycin B (hph) and for GFP (gfp). The protocol was optimized through different test conditions (type of membrane, concentration of the inducing agent acetosyringone and duration of the co-cultivation period). The higher transformation efficiencies were observed using cellulose ester membrane, 200 PM of acetosyringone and 96 hours of cocultivation. The transformants showed high mitotic stability (82%) and the insertion of the T-DNA was confirmed by PCR and GFP expression through epifluorescence microscopy observation. Moreover, it was observed the development of the fungus in inoculated oranges, showing the plant-pathogen interaction observed by epifluorescense microscopy. The establishment of the Agrobacterium-mediated transformation system for G. citricarpa represents an important step on the search for unveiling important genes of this fungus, such as those involved in the pathogenic mechanisms.
740

Caracterização do aparelho bucal e comportamento alimentar de Diaphorina citri Kuwayama (Hemiptera: Psyllidae) em Citrus sinensis (L.) Osbeck / Caracterization of the mouth aparatus and feeding behavior of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) on Citrus sinensis (L.) Osbeck

Bonani, Jean Patrick 30 April 2009 (has links)
O psilídeo Diaphorina citri é vetor das bactérias Candidatus Liberibacter asiaticus e Ca. L. americanus, associadas ao Huanglongbing (HLB) dos citros. Apesar da grande importância desta doença no mundo, sabe-se pouco sobre a atividade alimentar deste vetor, o que seria fundamental para entender o processo de transmissão desses patógenos e aprimorar estratégias de manejo da doença. Assim, esta pesquisa teve por objetivos: a) examinar aspectos morfológicos do aparato bucal de D. citri; b) caracterizar o seu comportamento alimentar em mudas de laranja doce (Citrus sinensis) através da técnica de Electrical Penetration Graph (EPG)-sistema DC; e c) avaliar o efeito da idade de folhas cítricas na penetração estiletar deste inseto e na eficiência de aquisição de Ca. L. asiaticus. Adultos de D. citri apresentam um rostro que se projeta logo após o par de coxas protoráxicas. Verificou-se que na extremidade distal desta estrutura há quatro pares de sensilas em simetria bilateral. O rostro abriga um feixe de quatro estiletes (2 mandíbulas e 2 maxilas) com comprimento médio de 512 µm. Os estiletes maxilares se acoplam formando os canais alimentar e salivar com diâmetros de 0,90 µm e 0,47 µm, respectivamente; esses dois canais se fundem próximo à extremidade distal de uma das maxilas para formar um canal comum, que se estende por, aproximadamente, 4,1 µm. No estudo de EPG, as formas de onda foram descritas quanto à amplitude, frequência, nível de voltagem e origem elétrica, sendo correlacionadas com atividades estiletares baseando-se em análises histológicas da posição da extremidade distal da bainha salivar no tecido vegetal e semelhanças com outras formas de onda descritas para afídeos. Cinco formas de onda foram descritas: (C) penetração intercelular no parênquima; (D) contato com o floema; (E1) salivação no floema; (E2) ingestão no floema; e (G) ingestão no xilema. Com um tempo médio de 206,1 min em 8 h de registro, a ingestão no floema (E2) é a principal atividade observada em D. citri. O tempo médio para atingir o floema desde a primeira prova é de 154 min, após 20,3 provas. D. citri mostra nítida preferência por folhas novas da porção superior da planta (71,3% dos indivíduos), e pela nervura principal na face abaxial das folhas (87,1%). Cortes histológicos revelam que folhas maduras apresentam lignificação nas paredes de células que compõem a camada de fibras, tecido que antecede o feixe floemático; já as folhas novas não apresentam esse espessamento, favorecendo o caminhamento estiletar rumo ao floema. Adultos de D. citri adquirem Ca. L. asiaticus com maior eficiência em folhas novas (assintomáticas) do que em folhas maduras (sintomáticas) de plantas infectadas. Aplicando-se a técnica de EPG, verificou-se que as folhas novas favorecem a alimentação floemática de D. citri; quase que a totalidade dos indivíduos avaliados sobre folhas novas assintomáticas encontraram o floema e permaneceram por mais tempo neste tecido, o que não foi constatado sobre folhas maduras sintomáticas. Esta pesquisa mostra que o comportamento alimentar de D. citri é influenciado pela idade das folhas cítricas, com implicações sobre a eficiência de aquisição da bactéria. / The Asian citrus psyllid, Diaphorina citri, is the vector of the phloem-limited bacteria Candidatus Liberibacter asiaticus and Ca. L. americanus, which are associated to the serious disease known as Citrus Huanglongbing (HLB). Despite the importance of this disease worldwide, little is known about the feeding activities of the vector, which is essential to understand transmission mechanisms and establish disease management strategies. Thus, the goals of this research were to examine the morphology of D. citri mouth apparatus, to characterize its probing behavior on sweet orange (Citrus sinensis) seedlings by using the Electrical Penetration Graph (EPG)-DC technique, and to assess the effect of citrus leaf age on the stylet penetration and efficiency of acquisition of Ca. L. asiaticus. D. citri shows a coneshaped rostrum that extends itself to behind the prothoracic pair of thighs. By electron microscopy, we found four pairs of sensilla symmetrically distributed on the distal end of the rostrum. The rostrum houses a stylet bundle comprised of two mandibulae and two maxillae with mean length of 512 µm. The two maxillary stylets are hold together and have internal grooves that form the food and salivary duct, with mean diameters of 0.9 and 0.47 µm, respectively. These two canals merge at a distance of 4.1 µm from the distal tip of the stylets, forming a common duct. In the EPG study, waveforms were described according to characteristics of amplitude, frequency, voltage level and electrical origin, and correlated with stylet activities based on histological analysis of salivary sheath termini in the plant tissue and similarities with EPG waveforms previously described for aphids. Five distinct waveform types were described: (C) intercellular stylet pathway through parenchyma, (D) phloem contact, (E1) salivation in the phloem sieve tubes, (E2) phloem sap ingestion, and (G) in xylem sap ingestion. Phloem sap ingestion (E2) is the main activity observed for D. citri, with an average time of 206.1 min in 8 h of recordings. Mean time to reach sieve tubes from the first probe is 154 min, after 20.3 probes. This insect shows a clear preference for young leaves of the upper portion of the plant (71.3% of the individuals), and main vein on the abaxial leaf surface (87.1%). Mature leaves show lignification in cell walls of the fiber layer adjacent to the phloem. In contrast, young leaves do not show cell wall thickening in this fiber layer, favoring stylet pathway towards the phloem. Adults of D. citri acquired L. Ca asiaticus with greater efficiency on young (asymptomatic) leaves than in mature (symptomatic) leaves from infected plants. Applying the EPG technique, it was found that young asymptomatic leaves favor phloem feeding by D. citri, since most individuals reached phloem sieve tubes and remained longer in this tissue; this was not the case for individuals confined on mature symptomatic leaves. This study shows that feeding behavior of D. citri is influenced by citrus leaf age, with implication on efficiency of bacterial acquisition from infected plants.

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