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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.
81

Etablissement du répertoire humain des procaryotes et diversité du microbiote digestif par approches variées / Establishment of the human prokaryotic repertoire and diversity of the human gut microbiota by various approaches

Hugon, Perrine 31 October 2014 (has links)
Au cours des dernières anneés, la taxonomie bactérienne a subi de profonds changements mais peu de consensus existent quant à la description précise des procaryotes. La diversité des procaryotes a été estimeé à 107 espèces, et la classification actuelle contient plus de 12 900 espèces officiellement reconnues. Ceci souligne l'absence d'un répertoire des procaryotes isolés chez l'homme. Nous avons constitué ce répertoire qui contient 2 156 espèces différentes réparties en 12 phyla,Notre second travail est la caractérisation du microbiote digestif par 5 approches varieés (cytométrie de flux, coloration de gram, TEM, qPCR, pyroséquençage). Nous avons analysé 16 selles de patients en comparant le taux de procaryotes de type gram positif/négatif. La moitié des procaryotes de type gram négatif n'est pas détecté par le pyroséquençage,alors qu'ils sont décrits comme les constituants majeurs de ce microbiote d'après les 1ères études réaliseés utilisant la culture.Dans notre 3ème travail, nous avons voulu montrer que l'utilisation de la culture bactérienne n'est pas inférieure aux techniques de séquençage pour étudier la diversité du microbiote digestif. Au total, depuis 4 ans, 685 échantillons ont été analysés et plus de 500 000 colonies ont été identifieés par MALDI-TOF. Ce travail a permis d'augmenter de 77,5 % le nombre d'espèces identifieés dans le tube digestif. Les nouvelles espèces sont décrites suivant le concept « taxonogenomics » incluant des donneés phénotypiques et le séquençage du génome. / Bacterial taxonomy has undergone tremendous changes over time, with little historical consensus regarding specific descriptions of prokaryotes. The prokaryotes have been estimated about 107 species, and the current classification contained more than 12,900 species. This highlights the absence of an exhaustive and specific database listing all prokaryotes associated with humans. We found than the human prokaryotic repertoire contained 2,156 species, divided among 12 different phyla.The second aim of our work was to characterize the human gut microbiota using 5 different techniques, including morphologic and molecular approaches (flow cytometry, gram staining, electron microscopy, qPCR and pyrosequencing). We analyzed 16 stools samples of patient and we copared the rate of gram-positive and gram-negative prokaryotes obtained with each technique. We found than by pyrosequencing only a half of gram-negative prokaryotes was detected.Our third goal was to demonstrate that bacterial culture was not inferior to pyrosequencing to describe the gut diversity. Culturomics concept created during the pioneer study has revolutionized the approach of the microbiota exploration. Since 4 years, we have performed the analyze of 685 different samples and identified more than 500,000 colonies using the MALDI-TOF mass spectrometry. We have increased by 77.5% the number of species isolated in the gut. Each new species will be described following our new concept named "taxonogenomics", including phenotypic data and genome sequencing.
82

Etude systématique des génomes bactériens / Systematic study of bacterial genomes

Rouli, Laetitia 31 October 2014 (has links)
Débutée en 2005, l'ère du pangénome a connu un important essor ces dernières années, notamment grâce aux progrès des techniques de séquençage haut débit. Le pangénome, qui est divisé en deux grandes parties, le core génome et le génome accessoire, offre un grand éventail d'utilisation. Au cours de ces trois dernières années, nous avons étudié cette gamme de possibilités en nous basant sur des pathogènes humains tel que Coxiella burnetii, Kingella kingae et Bacillus anthracis. Ainsi, outre la découverte d'une nouvelle espèce de Kingella et l'étude de quelques génomes spécifiques, nous nous sommes attardés sur le lien entre pangénome et pathogénicité, sur l'importance des SNPs (Single Nucleotide Polymorphism), ainsi que sur la corrélation entre pangénome et taxonomie et donc, par extension, nous avons étudié la notion d'espèce bactérienne. / The pangenome area began in 2005 and had known a huge increase thanks to the improvement of the Next Generation Sequencing methods. The pangenome, which is divided into two parts, the core and the accessory genome, offer a large panel of uses. During the last three years, we have studied all these possibilities. We based our work on human pathogens as Coxiella burnetii, Kingella kingae and Bacillus anthracis. Thus, in addition to the discovery of a new Kingella species and the study of some specific genomes, we studied in details the link between pangenome and pathogenicity, the importance of SNPs (Single Nucleotide Polymorphism) and the correlation between pangenome and taxonomy. Finally, we worked on the bacterial species definition.
83

Le pouvoir pathogène chez Ralstonia solanacearum phylotype II génomique intégrative et paysages transcriptomiques en relation avec l'adaptation à l'hôte / Pathogenicity of Ralstonia solanacearum phylotype : integrative genomics and transcriptomic landscapes associated with host specificity

Ailloud, Florent 03 April 2015 (has links)
Ralstonia solanacearum est une bactérie phytopathogène à la gamme d'hôte exceptionnellement large et à la répartition mondiale. Cet organisme présente une biologie à facettes multiples et s'est adapté à quasiment tous les types de sols, à la vie planctonique, et à de nombreux hôtes et plantes réservoirs. Cette capacité d'adaptation est attestée par une très forte hétérogénéité des souches qui unifient ce complexe d'espèces, aussi bien au plan de la diversité génétique, phénotypique, que de la gamme d'hôte. Des approches phylogénétiques ont montré une structuration de la population mondiale en quatre phylotypes qui correspondent globalement à l'origine géographique des souches. Les travaux de thèse portent sur des souches du phylotype II qui ont valeur de modèle expérimental car épidémiologiquement inféodées à un hôte particulier : souches Moko pathogènes du bananier, souches ‘Brown rot’ adaptées à la pomme de terre et souches émergentes NPB, un variant du pouvoir pathogène. La question de recherche centrale porte sur la compréhension des mécanismes d'adaptation à l'hôte. Pour cela, une dizaine de génomes ont été séquencés dans une perspective (i) de revisiter la taxonomie de ce complexe d'espèce, (ii) d'en faire une analyse génomique comparative et (iii) d'analyser les paysages transcriptomiques produits lors de l'infection (in planta). L'ensemble des ces approches complémentaires permettent ainsi d'intégrer la complexité génétique et phénotypique de l'organisme de manière plus systémique. / Ralstonia solanacearum is a plant pathogenic bacterium globally distributed with a particularly broad host range. This organism is biologically diverse and is adapted to all types of soil, to planktonic lifestyle and to many plant hosts and natural reservoirs. This bacterium is a species complex and its genetic, phenotypic and host range diversity is a direct consequence of adaptation mechanisms. Phylogenetic analyses have divided this species complex into four distinct phylotypes correlating mostly with strains’ geographical origin. This thesis focuses on using phylotype II strains as an experimental model due to their adaptation to specific hosts: Moko strains pathogenic to banana, ‘Brown rot’ strains adapted to potatoes and emergent pathological variant NPB strains. Our main research topic is the understanding of host adaptation processes. In order to tackle this problematic we sequenced about ten genomes as a starting point of (i) a taxonomic revision of the species complex (ii) a comparative genomic analysis and (iii) an in planta transcriptomic analysis. Together, these complementary approaches allow a more systemic view of this organism’s genetic and phenotypic complexity.
84

Klasifikace bakterií pomocí markerových genů / Bacteria Classification Based on Marker Genes

Pelantová, Lucie January 2020 (has links)
The aim of this work is proposal of new method for bacteria classification based on sequences of marker genes. For this purpose was chosen 10 marker genes. Resulting MultiGene classifier processes data set by dividing it in several groups and choosing gene for each group which can distinguish this group with best results. This work describes implementation of MultiGene classifier and its results in comparison with other bacteria classifiers and with classification based entirely on gene 16S rRNA.
85

Optimalizace metody PCR-RFLP pro taxonomické zařazení kvasinek / Optimalization of PCR-RFLP method for taxonomy of yeasts

Olivová, Radana January 2009 (has links)
This thesis deal with optimalization method PCR – RFLP for taxonomy enlistment of yeasts. Conventional identification methods for yeasts are time-consuming. Molecular biological method based on PCR are instrumental towards fast and precise identification as compared to conventional phenotypic methods. In this thesis molecular biological method PCR – RFLP was used for identification and enlistment of yeasts. This metod follow repeating spacers of ribozomal DNA of yeast, characteristic for each species and strain. By the help of PCR were amplified specific partitions of DNA. These fragments of DNA were split by restriction endonucleases and identified by horizontal electroforesis. In background of this thesis there are information about yeasts, their taxonomy and molecular biological methods.
86

Taxonomické zařazení kvasinek rodu Saccharomyces / Taxonomy of yeasts of the genus Saccharomyces

Augustová, Kamila January 2011 (has links)
The theoretical part discusses the yeasts and their taxonomic classification using traditional methods and using modern methods. Detail the work is concerned with descriptions of modern molecular-biology methods. The practical part was analyzed DNA by PCR-fingerprinting (rep-PCR) type of yeasts, which we received from the CCY and subsequent analysis of yeast samples obtained from grape musts. One of the grape must was obtained in 2009 (white grape variety) and the second in 2010 (red grape variety). Both grape musts come as integrated vineyards and organic. Grape musts samples were obtained from the winery Holánek from Ivaň. The cross-comparison of images PCR-fingerprint type yeasts and yeasts PCR-fingerprint samples using BioNumerics was to evaluate the results and conclude that the diversity of yeast flora in grape must.
87

Zur Klassifikation von Patterns

Fettke, Peter, Loos, Peter 24 September 2001 (has links)
"Patterns are proven solutions to recurring design problems." In der Literatur sind inzwischen zahlreiche Muster dokumentiert. Es ist offensichtlich, daß eine rein sequentielle Suche in dieser Mustermenge nicht effizient ist. Vielmehr wird ein Ordnungssystem benötigt, um für spezifische Problemstellungen geeignete Muster wiederaufzufinden. In dem Beitrag werden zunächst Anforderungen an ein Ordnungssystem für Muster entwickelt. Im zweiten Teil des Beitrages werden verschiedene Ordnungssysteme für Muster vorgestellt. Der dritte Teil des Beitrages bewertet die beschriebenen Ordnungssysteme im Hinblick auf die zuvor erarbeiteten Anforderungen. Abgeschlossen wird der Beitrag mit Überlegungen, wie ein leistungsfähiges Ordnungssystem für Muster ausgestaltet sein könnte.
88

Genetická a morfologická variabilita evropského rodu Cochlodina (Mollusca: Gastropoda: Clausiliidae) se zaměřením na druh C. laminata (Montagu, 1803) / Genetic and Morphological Variability of the European Genus Cochlodina (Mollusca: Gastropoda: Clausiliidae) with Focus on Species C. laminata (Montagu, 1803)

Szalontayová, Veronika January 2013 (has links)
This thesis focuses on the genetical and morphological diversity of plaited door snail (Cochlodina laminata). While small distribution ranges are typical for most species belonging to genus Cochlodina, the distribution range of C. laminata covers most of the European continent, except for its coolest and warmest parts. It has been previously suggested that this species might in fact be a complex of several species and large genetical as well as morphological diversity has been mentioned - however, yet undescribed - in previous studies. Sequences of two mitochondrial genes were used (16S rDNA, COI) and thirteen morphological characteritics have been assessed to investigate this diversity. I discovered that the current concept of C. laminata as a species is not in accordance with the discovered genetical nor morphological variability. The original species C. laminata/C. dubiosa form a common species complex and also interpretation of C. fimbriata will need to be assessed in more detail in the future. Other Central European species are valid species.
89

Fylogeneze a fylogeografie kaprovitých ryb rodu Pelasgus (Teleostei: Cyprinidae) / Phylogeny and phylogeography of the cyprinid fish genus Pelasgus (Teleostei: Cyprinidae)

Viñuela Rodríguez, Nuria January 2016 (has links)
The genus Pelasgus (Cyprinidae) is endemic to the southern part of the Balkan Peninsula and includes seven species. In this work, a multilocus approach has been applied to study phylogenetic relationships between the species and their populations and to revise their distribution areas. 180 specimens from 47 localities from 30 river drainages were analyzed, comprehensively covering the distribution range of the genus. Moreover, samples from type localities of all species were included in the analyses. Mitochondrial (cytochrome b) and nuclear markers (the first intron of ribosomal protein S7, recombination activating gene RAG1 and rhodopsin) were used. Existence of seven well supported lineages was revealed based on cytochrome b, which is the most variable marker. These lineages correspond to P. laconicus, P. marathonicus, P. minutus, P. stymphalicus, P. thesproticus, P. prespensis and Pelasgus sp. The most variable nuclear marker was first intron of S7, which provides almost the same results as cytochrome b, revealing six well supported lineages, whereas RAG1 and rhodopsin appear to be less informative, revealing only four well supported clades. These markers did not separate several species (P. marathonicus, P. stymphalicus, P. thesproticus, and Pelasgus sp.) due to low variability of the markers...
90

Systematika rodu Ramariopsis (Basidiomycota, Clavariaceae) ve střední Evropě / Systematics of the genus Ramariopsis (Basidiomycota, Clavariaceae) in central Europe

Matouš, Jan January 2017 (has links)
The genus Ramariopsis (Clavariaceae, Agaricales) having ramarioid, rarely clavarioid basidiomata includes about 15 species in central Europe. They are probably saprotrophic species which usually occur in grasslands or rarely open places in shrubs or deciduous forests. In this work, 88 collections of this genus mainly from the Czech Republic and Slovakia were studied, of which 57 sequences from the LSU and 36 from the ITS regions of the nuclear ribosomal RNA gene complex were obtained. Based on molecular-phylogenetic analyses using the maximum likelihood and bayesian methods, phylogenetic trees were created showing 16 well-supported clades. So detailed study on the phylogeny and relationships among species of the genus Ramariopsis is presented for first time, even within the world literature. Subsequent morphological analysis supported by SEM study of basidiospores showed that obtained clades represent nine species known in taxonomic literature, three so far non-described species (that were labelled with provisional names) and four clades whose interpretation is uncertain at the moment. Thus, seven clades represent cryptic diversity, which is a rather high extent. A new species Ramariopsis robusta Matouš et Holec has already been published and Ramariopsis rufipes and Ramariopsis kunzei var. bispora...

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