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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

Contributions to In Silico Genome Annotation

Kalkatawi, Manal M. 30 November 2017 (has links)
Genome annotation is an important topic since it provides information for the foundation of downstream genomic and biological research. It is considered as a way of summarizing part of existing knowledge about the genomic characteristics of an organism. Annotating different regions of a genome sequence is known as structural annotation, while identifying functions of these regions is considered as a functional annotation. In silico approaches can facilitate both tasks that otherwise would be difficult and timeconsuming. This study contributes to genome annotation by introducing several novel bioinformatics methods, some based on machine learning (ML) approaches. First, we present Dragon PolyA Spotter (DPS), a method for accurate identification of the polyadenylation signals (PAS) within human genomic DNA sequences. For this, we derived a novel feature-set able to characterize properties of the genomic region surrounding the PAS, enabling development of high accuracy optimized ML predictive models. DPS considerably outperformed the state-of-the-art results. The second contribution concerns developing generic models for structural annotation, i.e., the recognition of different genomic signals and regions (GSR) within eukaryotic DNA. We developed DeepGSR, a systematic framework that facilitates generating ML models to predict GSR with high accuracy. To the best of our knowledge, no available generic and automated method exists for such task that could facilitate the studies of newly sequenced organisms. The prediction module of DeepGSR uses deep learning algorithms to derive highly abstract features that depend mainly on proper data representation and hyperparameters calibration. DeepGSR, which was evaluated on recognition of PAS and translation initiation sites (TIS) in different organisms, yields a simpler and more precise representation of the problem under study, compared to some other hand-tailored models, while producing high accuracy prediction results. Finally, we focus on deriving a model capable of facilitating the functional annotation of prokaryotes. As far as we know, there is no fully automated system for detailed comparison of functional annotations generated by different methods. Hence, we developed BEACON, a method and supporting system that compares gene annotation from various methods to produce a more reliable and comprehensive annotation. Overall, our research contributed to different aspects of the genome annotation.
2

Scale effects on genomic modelling and prediction

Berger, Swetlana 03 February 2015 (has links)
In dieser Arbeit wird eine neue Methode für den skalenunabhängigen Vergleich von LD-Strukturen in unterschiedlichen genomischen Regionen vorgeschlagen. Verschiedene Aspekte durch Skalen verursachter Probleme – von der Präzision der Schätzung der Marke-reffekte bis zur Genauigkeit der Vorhersage für neue Individuen - wurden untersucht. Darüber hinaus, basierend auf den Leistungsvergleichen von unterschiedlichen statistischen Methoden, wurden Empfehlungen für die Verwendungen der untersuchten Methoden gege-ben. / In dieser Arbeit wird eine neue Methode für den skalenunabhängigen Vergleich von LD-Strukturen in unterschiedlichen genomischen Regionen vorgeschlagen. Verschiedene Aspekte durch Skalen verursachter Probleme – von der Präzision der Schätzung der Marke-reffekte bis zur Genauigkeit der Vorhersage für neue Individuen - wurden untersucht. Darüber hinaus, basierend auf den Leistungsvergleichen von unterschiedlichen statistischen Methoden, wurden Empfehlungen für die Verwendungen der untersuchten Methoden gegeben
3

Qualidade fisiológica e associação de Fusarium spp. a sementes de sorgo sacarino / Physiological quality and association of Fusarium spp. With seeds of sweet sorghum

Müller, Juceli 07 April 2017 (has links)
The present work aims to determine the physiological and sanitary quality of Sweet sorghum (Sorghum bicolor (L.) Moench) seeds, as well as to identify pathogens associated with seed, their transmission to seedlings and the subsequent pathogenicity of isolates obtained, In addition, molecularly identify the fungal species pathogenic to this crop. The experiments were carried out in the Teaching and Seed Research Laboratory (TSRL), of the Plant Engineering Department; In the Elocy Minussi Phytopathology Laboratory, Department of Plant Protection, and at the Biological Institute of São Paulo. Sweet sorghum seeds were used, all without chemical treatment. Sanitary quality was evaluated by sanity test, and physiological characteristics by germination and vigor tests (seedling length, dry mass, emergence, rate of emergence and accelerated aging). It was performed the test of transmission of the pathogens associated to the seeds and the subsequent pathogenicity of the obtained isolates, culminating with the molecular characterization of the identified pathogens, in which were sequenced the Internal Transcribed Spacer (ITS) genomic regions and the Elongation Factor 1 - alpha (TEF1-α) gene. The design used was the completely randomized design, with four cultivars of Sweet sorghum (BRS 506, F19, BRS 511 and BRS 509); For the evaluation of pathogenicity, the factorial scheme is represented by four cultivars and three isolates of Fusarium spp., besides the witness. The seeds of the BRS 509 cultivar were considered to have lower physiological quality than the other cultivars. The DNA sequencing allowed identifying the Fusarium thapsinum species as a pathogenic agent in the sweet sorghum crop, and proven its transmission via seeds. / O presente trabalho teve como objetivo determinar a qualidade fisiológica e sanitária de sementes de cultivares de sorgo sacarino (Sorghum bicolor (L.) Moench), bem como identificar os patógenos associados à semente, sua transmissão às plântulas e a posterior patogenicidade de isolados obtidos, além disso, identificar molecularmente as espécies fúngicas patogênicas a esta cultura. Os experimentos foram realizados no Laboratório Didático e de Pesquisas em Sementes (LDPS), do Departamento de Fitotecnia; no Laboratório de Fitopatologia Elocy Minussi, do Departamento de Defesa Fitossanitária e, no Instituto Biológico de São Paulo. Foram utilizadas sementes de sorgo sacarino, todas sem tratamento químico. A qualidade sanitária foi avaliada pelo teste de sanidade, e as características fisiológicas por meio dos testes de germinação e de vigor (comprimento de plântulas, massa seca, emergência, índice de velocidade de emergência e envelhecimento acelerado). Foi realizado o teste de transmissão dos patógenos associados à semente e a posterior patogenicidade dos isolados fúngicos obtidos, culminando com a caracterização molecular dos patógenos identificados, na qual foram sequenciadas as regiões genômicas Internal Transcribed Spacer (ITS) e o gene do fator de elongação 1-α (TEF1α). O delineamento utilizado foi o inteiramente casualizado com quatro cultivares de sorgo sacarino (BRS 506, Fepagro 19, BRS 511 e BRS 509); já para a avaliação da patogenicidade, o esquema fatorial foi representado pelas quatro cultivares e três isolados de Fusarium sp., além da testemunha. As sementes da cultivar BRS 509 foram consideradas de qualidade fisiológica inferior as demais cultivares. O sequenciamento de DNA permitiu identificar a espécie Fusarium thapsinum como agente patogênico na cultura do sorgo sacarino, sendo comprovada sua transmissão via sementes.
4

TOMATO FLESHY FRUIT QUALITY IMPROVEMENT: CHARACTERIZATION OF GENES AND GENOMIC REGIONS ASSOCIATED TO SPECIALIZED METABOLISM IN TOMATO FLESHY FRUIT

Fernández Moreno, Josefina Patricia 18 September 2016 (has links)
Tesis por compendio / [EN] Until recently, the genetic improvement of tomato (Solanum lycopersicum) was focused in agronomic traits, such as yield and biotic or abiotic stresses; therefore the interest in tomato fruit quality is relatively new. The tomato fruit surface can be considered both an agronomic trait as well as a quality trait, because it has an effect on consumer impression in terms of color and glossiness but also it underlies the resistance/sensitivity to cracking or water loss with consequences on fruit manipulation (e.g. transport and processing). The cuticle is deposited over the cell wall surrounding the epidermal cells and it is the first barrier in the plant-environment interface. The cuticle composition includes two main groups of metabolites: cuticular waxes and cutin. Other metabolites can be founded into the cuticle matrix, as triterpenoids and flavonoids. Those minor cuticular components are involved in the correct functionality of the cuticle. Understanding cuticle biosynthesis and genetic regulation requires the development of fast and simple analytical methodologies to study those specialized metabolites using large populations (e.g. mutant collections or introgression lines), together with the identification of genes and genomic regions responsible of their production. This thesis aims to contribute to our understanding of the molecular programs underlying tomato fruit quality by providing: i) a general protocol to profile cuticular waxes in different species, including tomato; ii) a QTL map for cuticular composition (i.e. cuticular waxes and cutin monomers) using the Solanum pennellii introgression line population; iii) a detailed protocol of the reverse genetic tool so-called Fruit-VIGS to assist in the study of gene function in tomato fruit; and iv) a thorough characterization of the first null allele for the transcription factor SlMYB12 (i.e. Slmyb12-pf) in tomato fruit which provides new insights into the regulation of the flavonoid biosynthetic pathway in the fruit peel by high resolution mass spectrometry and RNA-Seq approaches. / [ES] Hasta hace poco, la mejora genética del cultivo del tomate (Solanum lycopersicum) había estado centrada principalmente en caracteres agronómicos, como la productividad y la resistencia a estreses, tanto bióticos como abióticos. Así, el interés en la calidad del fruto de tomate es relativamente reciente. La superficie del fruto del tomate puede considerarse tanto un carácter agronómico como de calidad, pues influye en la primera impresión de los consumidores en términos de color y brillo, así como también en los procesos de resistencia o sensibilidad a la rotura ('cracking') o a la pérdida de agua. Estos factores determinan el aspecto del fruto y condicionan atributos relacionados con su manipulación (transporte y procesado). La cutícula se deposita sobre la pared celular de las células epidérmicas y es la primera barrera que interacciona con el ambiente. Está constituida por dos grandes tipos de metabolitos: las ceras cuticulares y la cutina. Otros metabolitos pueden aparecer embebidos en la matriz cuticular, como es el caso de los triterpenoides y los flavonoides. Estos metabolitos contribuyen a la correcta funcionalidad de la cutícula. La compresión de la biosíntesis y regulación génica de la cutícula requiere del desarrollo de metodologías de análisis sencillas y rápidas para el estudio de estos metabolitos especializados en grandes poblaciones (colecciones de mutantes o líneas de introgresión), así como para la identificación de genes y regiones génicas responsables de la producción y acumulación de dichos compuestos, pudiendo ser muy útiles para implementar programas de mejora de la calidad del tomate. El objetivo de esta tesis es contribuir a la comprensión sobre los programas moleculares subyacentes a la calidad del fruto de tomate, proporcionando: i) un protocolo general de análisis del contenido de ceras cuticulares en diferentes especies, incluyendo el tomate; ii) un mapa de QTL de la composición cuticular (incluyendo ceras y monómeros de cutina) obtenido con la población de líneas de introgresión de Solanum pennellii; iii) un protocolo detallado de uso de la herramienta de genética reversa Fruit-VIGS con el que realizar estudios de funciones génicas en fruto de tomate; y iv) una minuciosa caracterización de un nuevo alelo nulo del factor de transcripción SlMYB12 (Slmyb12-pf) en fruto de tomate, proporcionando nueva información sobre la regulación de la ruta biosintética de los flavonoides en la piel del fruto, utilizando espectrometría de masas de alta resolución y de nuevas tecnologías de secuenciación. / [CA] Fins fa poc de temps, la millora genètica de la tomata (Solanum lycopersicum) anava dirigida fonamentalment als caràcters de tipus agronòmic, com la productivitat i la tolerància a estressos biòtics o abiòtics, resultant que l'interés per la qualitat dels fruits és relativament nou. La superfície de la tomata pot ser considerada tant com un caràcter agronòmic com un de qualitat, ja que és l'aspecte de la superfície del fruit el que confereix al consumidor la primera impressió de color, brillantor, però és també la pell del fruit la responsable de la diferent susceptibilitat del fruit a desenvolupar clevills o que el fruit sofrisca més o menys pèrdues d'aigua, tot tenint importants conseqüències en la manipulació (i.e. transport i processament del fruit). La cutícula és dipositada per sobre de la paret cel·lular que envolta la capa de cèl·lules epidèrmiques i constitueix la primera barrera en la interfase planta-medi ambient. La composició de la cutícula presenta dos grups principals de metabòlits: les ceres i la cutina. També es poden trobar altres metabòlits els triterpenoids i el flavonoids. Aquests darrers components cuticulars menors són implicats en el correcte funcionament de la cutícula. Per tal de comprendre la biosíntesi i la regulació genètica de la cutícula cal desenvolupar tecnologies analítiques senzilles i rapides que permeten estudiar aquests metabòlits especialitzats en poblacions grans de plantes (i.e. Col·leccions de mutants o de línies d'introgressió), a més de la identificació de gens i regions genòmiques que són responsables de la seua producció. Aquesta tesi té com a objectiu contribuir a millorar la nostra comprensió dels programes moleculars que afecten determinats aspectes de la qualitat de la tomata mitjançant els següents objectius: i) proporcionar un protocol general per obtenir perfils de ceres cuticulars en diferents espècies, inclosa la tomata; ii) obtenir un mapa de QTL per a la composició cuticular (i.e. ceres cuticulars i monòmers de cutina) mitjançant la utilització de la població de línies d'introgressió de Solanum pennelli; iii) descriure amb detall el protocol d'una eina de revers genètica denominada Fruit-VIGS que resulta molt adequada per estudiar funció gènica a la tomata; y iv) fer una caracterització exhaustiva del primer al·lel nul del factor de transcripció SlMYB12 (ie. Slmyb12-pf) en tomata la qual proporciona informació nova sobre la regulació de la ruta de biosíntesi de flavonoides en la pell de la tomata mitjançant espectrometria de masses d'alta resolució i RNAseq. / Fernández Moreno, JP. (2015). TOMATO FLESHY FRUIT QUALITY IMPROVEMENT: CHARACTERIZATION OF GENES AND GENOMIC REGIONS ASSOCIATED TO SPECIALIZED METABOLISM IN TOMATO FLESHY FRUIT [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/55505 / TESIS / Premios Extraordinarios de tesis doctorales / Compendio

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