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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.
1

Alterações moleculares, físico-químicas e fisiológicas em melões e tomates: relações com etileno e citocininas / Molecular alterations, physicochemical and physiological in melons and tomatoes: relations with ethylene and cytokinin

Gonçalves, Ciane Xavier 08 March 2013 (has links)
Made available in DSpace on 2014-08-20T13:32:48Z (GMT). No. of bitstreams: 1 tese_ciane_xavier_goncalves.pdf: 2548463 bytes, checksum: 75f8193b6bd48d05e54efb24e14099b9 (MD5) Previous issue date: 2013-03-08 / Ethylene is the inductor and acceleratorhormone of the maturation and senescence of climacteric fruits, as is the case of Cantaloupe melons (Cucumismelo var. Cantalupensis, Naud cv. Vedrantais) and tomatoes (LicopersicumesculentumL. cv. Micro-Tom). It is known that the reduction of production and/or the action of this hormone prolongs the shelf life of these fruits. Thus, in order to reduce the production of such hydrocarbon, were genetically transformed melon trees with clones of the ACC oxidase 'antisense', of melon (pMEL1AS, Ayubet al., 1996) and of apple (pAP4AS, Silva et al., 2004). As expected, in both cases, the ethylene production was reduced, prolonging shelf life of fruits in 7 days. However, the production of volatile compounds was also affected. The transgenic melons produced, on average, 70% less esters than the WT, independently of having been transformed with pMEL1AS or pAP4AS. As the intervention made acted in the reduction of the production of ethylene. It was emitted the hypothesis that, with the supplementation of the hormone, the synthesis of flavors would be restored. Such fact was proven in pMEL1AS melons, but not in pAP4AS. The exact causes of this difference were not yet made clear. It is believed that because of the greater reduction of the ethylene production in the fruit pAP4AS, besides affecting genes directly related to the ripening classical metabolic pathways, genes related to other pathways of synthesis of hormones have also been affected, as is the case of cytokininsor polyamines. By observation of the phenotype of pAP4AS plants we realized that these had more vegetative growth and lateral sproutings. Considering such observations, it was launched the hypothesis that with the increase of the levels of cytokinins one could interfere in the responses to ethylene, delaying the normal evolution of the fruits. In pAP4AS melons it was proved that there are higher levels of cytokinins, both in the roots and fruits.However, to confirm that these changes are effectively consequence of higher levels of cytokinins, exogenous application of that growth regulators was made. Nevertheless, were not observed any expected responses. So we decided to test the application of cytokinin in another plant model, the tomato tree cv. Micro- Tom, who is also a producer of climacteric fruits and that provides greater ease of cultivation and obtainment of greater quantity of fruit in protected environments and in areas with limited space. As molecular variables for assessment of the treatments in melons were determined the accumulation of transcript of genes of HPL, LOX and AAT, besides the ACCO and ACCS. In tomatoes, were performed physicochemical analyzes. For melons, when quantifying the accumulation of transcripts of genes of ACC synthase (ACCS), it was found that genes ACCS1 and ACCS3 showed higher expressions in WT fruits, suggesting that they have a strong relation with the evolution of the climacteric crisis. Moreover, the gene ACCS5 was more expressed in fruits pMEL1AS and pAP4AS, indicating that it is negatively regulated by ethylene. For the other variables evaluated (total soluble solids, color, carotenoids, chlorophylls, pulp firmness) during the ripening on the plant, there were no marking differences between pMEL1AS and pAP4AS. After harvesting and treatment of pMEL1AS fruits with ethylene, there was a degreening of the peel and increase of the production of esters, correlated with higher levels of transcripts of the genes of HPL, LOX, AAT1, AAT2, AAT3 and AAT4. In pAP4AS fruits, the levels of these transcripts was significantly lower, not having been observed degreeningor yellowing, nor restoration of the synthesis of esters. In these fruits (pAP4AS) it was detected a higher concentration of zeatin and zeatin ribose than in pMEL1AS and WT. For tomato plants, in which was done application of cytokinins, there was prolongation of the vegetative cycle and delay in the maturation. The fruits from the treated plants also prolonged the maturation cycle, but did not decrease sensitivity to ethylene action. It is believed that cytokinins may be the responsible ones for lower sensitivity to ethylene in melons, but this hypothesis was not confirmed and must be tested with greater profundity. The attempt to prove it using tomato plants as model was not efficient. / O etileno é o hormônio indutor e acelerador da maturação e senescência de frutos climatéricos, como é o caso de melões Cantaloupe (Cucumis melo var. Cantalupensis, Naud cv. Vedrantais) e de tomates (Licopersicum esculentum L. cv. Micro-Tom). Sabe-se que a redução de produção e/ou a ação desse hormônio prolonga o período de conservação desses frutos. Assim, com o objetivo de reduzir a produção desse hidrocarboneto, foram transformados geneticamente meloeiros com clones da ACC oxidase antisense , de melão (pMEL1AS, Ayub et al., 1996) e de maçã (pAP4AS, Silva et al., 2004). Como era esperado, em ambos os casos, a produção de etileno foi reduzida, prolongando a vida de prateleira dos frutos em 7 dias. Entretanto, a produção de compostos voláteis também foi afetada. Os melões transgênicos produziram, em média, 70% menos ésteres do que os não transformados (NT), independentemente de terem sido transformados com o pMEL1AS ou pAP4AS. Como a intervenção feita agiu na redução da produção do etileno, emitiu-se a hipótese de que com a suplementação do hormônio, a síntese de aromas seria restaurada. Tal hipótese foi comprovada em melões pMEL1AS, mas não nos pAP4AS. As causas exatas dessa diferença ainda não foram esclerecidas. Acredita-se que pela maior redução da produção de etileno nos frutos pAP4AS, além de ter-se afetado genes diretamente relacionados com as vias metabólicas clássicas do amadurecimento, genes relacionados a outras vias de síntese de hormônios também tenham sido afetados, como é o caso de citocininas ou poliaminas. Pela observação do fenótipo de plantas pAP4AS percebeu-se que essas tiveram maior crescimento vegetativo e brotações laterais. Considerando-se tais observações, lançou-se a hipótese de que com o aumento dos níveis de citocininas poderia interferir nas respostas ao etileno, retardando a evolução normal dos frutos. Em melões pAP4AS comprovou-se haver maiores teores de citocininas, tanto nas raízes quanto nos frutos. Porém, para confirmar que essas alterações são efetivamente consequência de maiores teores de citocininas, fez-se aplicação exógena desse regulador de crescimento. No entanto, não se observaram as respostas esperadas. Então optou-se por testar a aplicação de citocininas noutro modelo vegetal, o tomateiro cv. Micro-Tom, que também é produtor de frutos climatéricos e que propicia maior facilidade de cultivo e obtenção de maior quantidade de frutos em ambientes protegidos e em áreas com limitação de espaço. Como variáveis moleculares para avaliação dos tratamentos em melões determinou-se o acúmulo de transcritos de genes de HPL, LOX e AAT, além da ACCO e ACCS. Em tomates, foram realizadas análises físico-quimicas. Para melões, ao se quantificar o acúmulo de transcritos de genes da ACC sintase (ACCS), verificou-se que os genes ACCS1 e ACCS3 apresentaram maiores expressões nos frutos NT, sugerindo que esses têm forte relação com a evolução da crise climatérica. Por outro lado, o gene ACCS5 foi mais expresso nos frutos pMEL1AS e pAP4AS, indicando que é regulado negativamente pelo etileno. Para as demais variáveis avaliadas (sólidos solúveis totais, coloração, carotenóides, clorofilas, firmeza de polpa) durante o amadurecimento na planta, não houve diferenças marcantes entre pMEL1AS e pAP4AS. Após a colheita e tratamento dos frutos pMEL1AS com etileno, houve desverdeamento da casca, e aumento da produção de ésteres, correlacionado com maiores níveis de transcritos dos genes da HPL, LOX, AAT1, AAT2, AAT3 e AAT4. Nos frutos pAP4AS, os níveis desses transcritos foi significativamente inferior, não tendo-se observado desverdeamento, nem amarelamento, tampouco restauro da síntese de ésteres. Nesses frutos (pAP4AS) foi detectada uma maior concentração de zeatina e zeatina ribose do que nos pMEL1AS e nos NT. Para tomateiros, nos quais fez-se a aplicação de citocininas, houve prolongamento do ciclo vegetativo e retardamento da maturação. Nos frutos provenientes de plantas tratadas verificou-se que a ação do etileno foi regulada, em particular em relação à variação dos principais pigmentos desse fruto (β-caroteno e licopeno). Desse modo, acredita-se que as citocininas possam ser as responsáveis pela menor sensibilidade ao etileno em melões, mas essa hipótese precisa ser testada com maior profundidade. A tentativa de prová-la usando tomateiros como modelo não foi totalmente eficiente.
2

A Comparative Analysis of the Integration of Faith and Learning Between ACSI and ACCS Accredited Schools

Peterson, Daniel Carl 23 May 2012 (has links)
The purpose of this descriptive quantitative study was to analyze and compare the integration of faith and learning occurring in Christian schools accredited by the Association of Christian Schools International (ACSI) and classical Christian schools accredited by the Association of Classical and Christian Schools (ACCS). ACSI represents the larger Christian school movement while ACCS represents the larger classical Christian school movement. The biblical metanarrative of the Christian faith - creation, fall, redemption, and consummation - set the biblical and theological framework for the integration of faith and learning in this study. A precedent literature review pointed to a gap in the literature base regarding the integration of faith and learning occurring between ACSI and ACCS schools. Essentially, the study sought to describe the degree to which accredited K-12 ACSI and ACCS schools integrate faith and learning and then compare the level of integration of faith and learning between ACSI and ACCS accredited schools. The research design for the study was a one-phase quantitative study utilizing both descriptive and inferential statistics. The research instrument was originally developed and used by Raquel Bouvert de Korniejczuk and later modified by Mark Eckel to determine the level of integration of faith and learning teachers are practicing in ACSI and ACCS schools. Overall, the data indicated teachers were practicing a high level of integration of faith and learning in their pedagogy in both ACSI and ACCS accredited schools. The data indicated that as the years taught at Christian schools and classical Christian schools increased the level of integration of faith and learning increased. Gender was not a factor in the level of integration of faith and learning. Teachers that did not attend a Christian school growing up self-reported a higher level of integration of faith and learning than teachers who did attend a Christian school growing up. Teachers, both in Christian schools and classical Christian schools, receiving training in the area of the integration of faith and learning indicated a higher overall level of integration of faith and learning. KEYWORDS: Association of Christian Schools International (ACSI), Association of Classical and Christian Schools (ACCS), biblical worldview, Christian education, Christian school, classical Christian school, integration of faith and learning, Trivium
3

Spiritual Formation: A Comparative Study of Modern and Classical Christian Schools

Dernlan, Timothy James 26 April 2013 (has links)
No description available.

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