Global ETD Search

101	Caractérisations et impacts des transposons à ADN chez Ophiostoma ulmi et O. novo-ulmi, principaux agents de la maladie hollandaise de l'orme Bouvet, Guillaume 12 April 2018 (has links) Des éléments mobiles de type 2 ont été mis en évidence chez Ophiostoma ulmi et O. novoulmi, agents pathogènes de la maladie hollandaise de l'orme. Dans un premier temps, ces transposons à ADN, nommés OPHIOl, OPHI02 et OPHI03, ont été subséquemment caractérisés, tant au niveau structural qu'au niveau de leur répartition dans les espèces concernées. L'étude approfondie de leur séquence a permis de faire ressortir des mutations particulières de type RIP (Repeat induced point mutations) uniquement présentes chez OPHI03. Ces dernières, ont par ailleurs, permis de mettre au point une nouvelle technique de visualisation de ce type de mutations (CTS visualizatiori), applicable à l'ensemble de ces éléments mobiles. Dans un second temps, la mobilité & OPHIOl et OPHI02 a fait l'objet d'une étude détaillée. Grâce à divers stress abiotiques, nous avons démontré que ces éléments sont mobiles au sein des génomes des champignons responsables de la maladie hollandaise de l'orme. En dernier lieu, des analyses bioinformatiques ont permis de mettre en évidence des zones de sélection positive au sein de domaines précis des transposases, l'enzyme requise pour la mobilité d'OPHIOl et d'OPHI02. L'ensemble de ces résultats a permis d'accroître la connaissance des TE ainsi que d'essayer de comprendre la dynamique complexe existant entre les transposons et leurs génomes hôtes. / Type 2 mobile elements were detected in Ophiostoma ulmi and O. novo-ulmi sp., the causal agents of the Dutch elm disease. Firstly, the structure and the distribution in Ophiostoma species of these DNA transposons, named OPHIOl, OPHI02 and OPHI03, were characterized. A precise analysis of their sequence demonstrated some particular RIP mutations (Repeat induced point mutations) in the case of OPHI03. These mutations allowed us to develop a new visualization (CTS visualization) for these types of mutations, applicable to ail mobile elements. Secondly, the mobility of OPHIOl and OPHIOl was the main investigation of a detailed study. We demonstrated that abiotic stresses have a direct impact on the induction of mobility of the transposons within Ophiostoma sp. To finish our investigation, bioinformatics analyses were performed on OPHIOl and OPHIOl (considered to be active transposons) and allowed the presence of regions under positive selection inside the transposase (enzyme required for their mobility). Taken together, these results lead to a better understanding of a part of the complex dynamics that links mobile elements to their host genomes. SD 121 UL 2007 B782 Éléments génétiques mobiles Transposons
102	Lokalizace metylačních míst transposonů / Localization of Methylation Sites in Transposons Kmeť, Miroslav January 2015 (has links) This master's thesis deals with the creation of a tool for the extraction of methylation level from transposon sequences. Transposons are DNA elements with ability to move or copy themselves and their activity is regulated by DNA methylation. Sequence methylation information is stored in the bisulfite data and their processing is done with parts of two existing tools in a combination with implemented modules. Created tool takes into consideration unique challenges brought in the methylation calling process by transposable elements and it's functionality is presented on a set of experiments with simulated and real data.
103	Chromosomal Integration and In Vivo Transcriptional Optimization of Metabolic Pathways in E. Coli O'Dell, Philip John 26 July 2022 (has links) No description available. Chemical Engineering Microbiology bioproduction E. coli chromosomal integration biosynthetic pathway small molecule production psilocybin norbaeocystin expression vector transposons cas9 homologous recombination transcriptional optimization
104	Genome engineering and gene drive in the mosquito aedes aegypti St John, Oliver Tudor Lockhart January 2012 (has links) Genetic control strategies are a novel method for reducing populations of pest insects such as the yellow fever mosquito Aedes aegypti, a major vector of several important arboviral diseases. This thesis describes efforts to develop new tools to engineer the Ae. aegypti genome and to better understand existing tools, and furthermore to use these to engineer a gene drive system in Ae. aegypti. The piggyBac transposon was found to be extremely stable in the germline of Ae. aegypti, and transposons engineered into the germline could not be remobilized with either an endogenous or exogenous source of piggyBac transposase. Conversely, somatic remobilization of piggyBac transposons was found to be readily detectable in the presence of a source of active transposase, the first report of such remobilization in Ae. aegypti. Toward new tools for genome engineering, the site-specific integrase from the phage φC31 was successfully used to promote exchange between a transgene cassette inserted into the genome of Ae. aegypti and a cassette in a plasmid vector, in the first demonstration of recombinase mediated cassette exchange technology in a pest insect species. The integrases from phages φRV1 and Bxb1 were not found to be active in the germline of the mosquito. Finally, development of a gene drive system in Ae. aegypti using an RNAi-mediated killer-rescue mechanism was attempted. Tissue-specific expression of tTAV-regulated-toxic effectors genes, using the promoter regions of the blood meal induced genes Carboxypeptidase A-1, 30Kb and Vitellogenin A, was possible, but sex-specificity was not achieved. A blood meal inducible lethal phenotype was not possible using the chosen promoters, with expression of the effectors either leading to death in early development or to a sublethal phenotype. RNAi against tTAV fused to the Mnp fragment of the dengue virus’ genome was tissue specific, but was found to be highly effective in the fat body suggesting that the Vitellogenin A was the best candidate for the engineering of killer-rescue systems in the mosquito. 572.8
105	Analýza dat ze sekvenování příští generace ke studiu aktivity transposonů v nádorových buňkách / Analysis of NGS data for study of transposon activity in cancer cells Hrazdilová, Ivana January 2013 (has links) Theoretical part of this diploma thesis gives a brief characteristic of human mobile elements (transposons), which represents nearly 50% of human genome. It provides basic transposon clasification and describes types of transposons present in hunam genome, as well as mobilization, activation and regulation mechanisms. The work also deals with the domestication of transposons, describes the ways in which TE contribute to DNA damage and summarizes the diseases caused by mutagenic activity of transposons in the human genome. Conclusion of theoretical part describes next-generation sequencing technologies (NGS). As practical part, data from RNA-seq experimet were analyzed in order to compare differen transposon activity in normal and cancer cells from prostate and colorectal tissues. As like as publicly available sophisticated tools (TopHat), new scripts were created to analyze these data. The results show that cancer cells exhibit overexpression of transposons. This corresponds with the published results and suggests a connection of transposon activation with cancer development.
106	Mutation and Genome Evolution Yampolsky, L. Y. 14 April 2016 (has links) Genome composition and architecture is shaped by two types of processes: those that introduce heritable changes (mutagenesis) and those that determine the fate of such changes in the populations (genetic drift and selection). Chemical and biological properties of mutagenesis determines the frequencies at which different type of mutations occur, which, in turn, determines their rates of fixation by drift and affects the spectrum of mutations available for selection to operate on. As the result, genomes of living organisms carry many signatures mutagenesis. copy number variation CpG dinucleotides deletions DNA repair DNA replication ectopic crossing-over gene conversion genome insertions isochores microsatellites mutations segmental duplications selection strand asymmetry transitions transposons Biological Sciences
107	Strategies of Sexual Reproduction in Aphids / Fortpflanzungsstrategien der Sexuellen Generation von Blattläusen Dagg, Joachim 30 October 2002 (has links) No description available. 570 Biowissenschaften, Biologie Mathematics and Computer Science Strategie Kopulationsdauer Spermienkonkurrenz Spermien-Kooperation Marginal Value Theorem Paarungsverhalten Partner-Bewachung Partnerwahl Konkurrenz Geschlechter-Verhältnis Geschlechter-Verteilung springende Gene Transposons; strategy copula duration sperm competition sperm co-operation marginal value theorem courtship mate guarding mate choice mate competition kin competition sex ratio sex allocation jumping genes transposon ancient asexual scandals paradox of sexual reproduction replicator interactor Uroleucon cirsii Uroleucon cichorii Euceraphis betulae Schizolachnus obscurus Rhopalosiphum padi; 42.21 Evolution 42.66 Ethologie 42.67 Fortpflanzung 42.75 Insecta 42.97 Ökologie: Sonstiges

Page generated in 0.0431 seconds