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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

Development and characterization of DNA markers for two avian species

Kamara, Davida F. 24 July 2006 (has links)
Central to the application of genomics to animal agriculture are DNA markers, especially microsatellites and single nucleotide polymorphisms. These markers are the resources necessary for constructing genetic maps and for determining how improved and unimproved animal breeds are related. Here, DNA markers were developed for two avian species, the turkey, Meleagris gallopavo, and the budgerigar (budgie), Melopsittacus undulatus. Genomic libraries enriched for simple sequence repeats were used to generate about 70 budgie sequences of a total length of 38 kb. From these sequences, 9 primer pairs were designed and used to screen for informativeness in a panel of DNA samples from unrelated budgie samples. All but one of the nine primers evaluated were polymorphic with the number of alleles ranging from two to four. Comparative analysis involving the use of these budgie primers showed moderate sequence similarity to turkey and chicken. The genomic libraries and the comparative sequences provide useful genomic reagents that could be used to construct a budgie genome map. In the turkey, ten previously described microsatellites and a gene-based single nucleotide polymorphism (SNP) were used to evaluate the relatedness of heritage varieties to a commercial strain. Estimates of Nei's genetic distance (D) and genetic differentiation (Rst) between populations using microsatellite markers showed that the commercial strain is genetically more closely related to the Bourbon Red and Narragansett and least related to the Royal palm and Spanish Black. Gene flow (Nm) level was highest between the commercial and Bourbon Red populations. The SNP analysis by PCR-RFLP revealed that the commercial strain was more closely related to the Spanish black and Narragansett and least related to the Bourbon red and Blue slate. Though results of the two marker systems, microsatellite and SNP, were inconsistent, they provide insights into using heritage turkeys to genetically improve commercial populations by introgression. The present thesis investigation showed that DNA markers provide a strong opportunity to develop genomic reagents needed to test hypotheses in little-studied agriculturally important and model avian species. / Master of Science
2

Isolamento e caracterização de microssatélites em Búfalo de rio (Bubulus bubalis) a partir da construção de bibliotecas genômicas parciais com hibridização seletiva /

Venancio, Larissa Paola Rodrigues. January 2008 (has links)
Resumo: O Brasil é o país com o maior rebanho de búfalo de rio, Bubalus bubalis, no continente americano e também o maior produtor deste animal fora do continente asiático. A produção de leite e derivados vem aumentando devido à potencialidade dessa espécie em produzir leite com baixos custos e elevado rendimento industrial. Apesar das características economicamente importantes inerentes ao búfalo, as pesquisas científicas são limitadas em muitos países onde o búfalo é economicamente importante e como conseqüência a pesquisa genômica encontrase defasada quando comparado com outras espécies de interesse econômico. Marcadores moleculares são essenciais para avaliar informações qualitativas e quantitativas da diversidade molecular com o objetivo de aperfeiçoar a utilização e conservação da variabilidade genética e o relacionamento entre vários rebanhos. Microssatélites diferem dos outros tipos de seqüências de DNA por seu extenso polimorfismo dentro e entre populações, sendo considerados excelentes tipos de marcadores moleculares. O presente estudo teve como objetivos construir bibliotecas genômicas parciais enriquecidas com microssatélites, isolar e caracterizar os microssatélites obtidos, além de determinar as condições de amplificação por PCR para alguns dos locos isolados da biblioteca. Foram desenvolvidas 6 bibliotecas genômicas parciais - (CA)15 , (CT)15 , (AGG)8 , (GATA)8 , (GAAA)8, (AAAAC)8. O processo de clonagem gerou um total de 1.824 clones recombinantes, sendo que 954 foram seqüenciados para identificação de microssatélites. Cento e treze microssatélites foram encontrados. Desses, foram identificados 96 com unidade de repetição dinucleotídica (84,95%), 10 repetições trinucleotídicas (8,85%), 6 repetições tetranucleotídicas (5,3%) e 1 repetição pentanucleotídica (0,89%). As seqüências de microssatélites... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Brazil is the largest river buffalo (Bubalus bubalis) breeding center outside the Asian continent, the origin of the domestic buffalo. All buffalo breeds have a strong milk/meat attributes. Their extensive use in agriculture world wide, and especially in developing countries, begs for genetic resources to evaluate and improve traits important to local and regional economies. Among the different types of DNA markers, microsatellites are useful for studying genetic variability within and between populations due its high heterozygosity. The goal of this study was to construct partial genomic libraries enriched with repeated sequences to isolate and characterize microsatellites for river buffalo. The cloning process generated a total of 1824 recombinant clones, from which 954 were sequenced for the microsatellites search. One hundred and thirteen new microsatellites were isolated, containing the following type of repeats: dinucleotide repeats (96 sequences - 84.95%), trinucleotide repeats (10 sequences - 8.85%), tetranucleotide repeats (6 sequences - 5.3%) and pentanucleotide repeats (1 sequence - 0.89%). The new microsatellites were structurally categorized into 3 categories: pure repeats (90 sequences - 79.64%), pure interrupted (21 sequences - 18.59%) and compound interrupted repeats (2 sequence - 1.77%). PCR primer pairs were designed for ten microsatellites, from which four had the PCR conditions optimized. The microsatellites isolated in this study will be used to evaluate the genetic variability of Brazilian populations of river buffalo and to the gene mapping program established for this specie. / Orientador: Maria Elisabete Jorge Amaral / Coorientador: Artur Luiz da Costa da Silva / Banca: Vera Fernanda Martins Hossepian de Lima / Banca: Sandra Regina de Carvalho Marchesin / Mestre
3

Caractérisation et analyse des effets probiotiques de souches de Lactobacillus et de Bifidobacterium / Characterization and analysis of probiotics effects of Lactobacillus and Bifidobacterium strains

Laval, Laure 08 November 2013 (has links)
Les bénéfices attribués aux probiotiques sont nombreux : effets bénéfiques sur le microbiote intestinal, confort digestif, modulation du système immunitaire et prévention des infections intestinales. Ces effets divers et variés sont souches-spécifiques. Actuellement, de nombreuses études visent à mieux caractériser ces effets probiotiques.Ces travaux avaient pour objectif de déterminer et d’analyser les effets probiotiques de trois souches de la collection Danone : la souche de Lactobacillus paracasei CNCM I-3689, la souche de L. rhamnosus CNCM I-3690 ainsi que la souche de Bifidobacterium animalis subps. lactis CNCM I-2494. Dans un premier temps, leurs effets ont été caractérisés dans des modèles in vitro pour des propriétés anti-pathogènes, des propriétés d’immuno-modulation ainsi que pour des propriétés de protection de la barrière épithéliale intestinale. Dans un second temps, leurs effets de la protection de la barrière ont été confirmés dans un modèle murin de faible inflammation.Une analyse des mécanismes sous-jacents à ces effets à la fois chez la souche probiotique et chez l’hôte a été initiée par la construction et l’analyse fonctionnelle de banques génomiques bactériennes ainsi que par l’étude de la modulation des gènes impliqués dans le maintien de la barrière intestinale chez l’hôte. / Health benefits of probiotic bacteria are numerous: beneficial effects on the intestinal microbiota, digestive comfort, modulation of the immune system and prevention of winter infection. These diverse and various effects are strain-specific. Nowadays, numerous studies aim at better characterizing those probiotics effects.This project aimed at identifying and analyzing the probiotic effects of three strains from Danone collection: Lactobacillus paracasei CNCM I-3689, L. rhamnosus CNCM I-3690 and Bifidobacterium animalis subsp. lactis CNCM I-2494. First, their effects were assessed in in vitro models for immunomodulation properties, antipathogens activity and intestinal barrier protection. Secondly, their beneficial effects were confirmed in low-grade inflammation murine model.The analysis of the underlying mechanisms has been initiated both in the bacterial strains by the construction and the functional analysis of genomic libraries and in the host by measuring the modulation of the genes involved in the intestinal barrier maintain.
4

Isolamento e caracterização de microssatélites em Búfalo de rio (Bubulus bubalis) a partir da construção de bibliotecas genômicas parciais com hibridização seletiva

Venancio, Larissa Paola Rodrigues [UNESP] 29 February 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-29Bitstream added on 2014-06-13T18:53:57Z : No. of bitstreams: 1 venancio_lpr_me_sjrp.pdf: 1068047 bytes, checksum: d85b41abf589322ab5174b5d9c2b731e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Nsf - Nacional Science Foundation / O Brasil é o país com o maior rebanho de búfalo de rio, Bubalus bubalis, no continente americano e também o maior produtor deste animal fora do continente asiático. A produção de leite e derivados vem aumentando devido à potencialidade dessa espécie em produzir leite com baixos custos e elevado rendimento industrial. Apesar das características economicamente importantes inerentes ao búfalo, as pesquisas científicas são limitadas em muitos países onde o búfalo é economicamente importante e como conseqüência a pesquisa genômica encontrase defasada quando comparado com outras espécies de interesse econômico. Marcadores moleculares são essenciais para avaliar informações qualitativas e quantitativas da diversidade molecular com o objetivo de aperfeiçoar a utilização e conservação da variabilidade genética e o relacionamento entre vários rebanhos. Microssatélites diferem dos outros tipos de seqüências de DNA por seu extenso polimorfismo dentro e entre populações, sendo considerados excelentes tipos de marcadores moleculares. O presente estudo teve como objetivos construir bibliotecas genômicas parciais enriquecidas com microssatélites, isolar e caracterizar os microssatélites obtidos, além de determinar as condições de amplificação por PCR para alguns dos locos isolados da biblioteca. Foram desenvolvidas 6 bibliotecas genômicas parciais – (CA)15 , (CT)15 , (AGG)8 , (GATA)8 , (GAAA)8, (AAAAC)8. O processo de clonagem gerou um total de 1.824 clones recombinantes, sendo que 954 foram seqüenciados para identificação de microssatélites. Cento e treze microssatélites foram encontrados. Desses, foram identificados 96 com unidade de repetição dinucleotídica (84,95%), 10 repetições trinucleotídicas (8,85%), 6 repetições tetranucleotídicas (5,3%) e 1 repetição pentanucleotídica (0,89%). As seqüências de microssatélites... / Brazil is the largest river buffalo (Bubalus bubalis) breeding center outside the Asian continent, the origin of the domestic buffalo. All buffalo breeds have a strong milk/meat attributes. Their extensive use in agriculture world wide, and especially in developing countries, begs for genetic resources to evaluate and improve traits important to local and regional economies. Among the different types of DNA markers, microsatellites are useful for studying genetic variability within and between populations due its high heterozygosity. The goal of this study was to construct partial genomic libraries enriched with repeated sequences to isolate and characterize microsatellites for river buffalo. The cloning process generated a total of 1824 recombinant clones, from which 954 were sequenced for the microsatellites search. One hundred and thirteen new microsatellites were isolated, containing the following type of repeats: dinucleotide repeats (96 sequences - 84.95%), trinucleotide repeats (10 sequences - 8.85%), tetranucleotide repeats (6 sequences – 5.3%) and pentanucleotide repeats (1 sequence - 0.89%). The new microsatellites were structurally categorized into 3 categories: pure repeats (90 sequences - 79.64%), pure interrupted (21 sequences - 18.59%) and compound interrupted repeats (2 sequence – 1.77%). PCR primer pairs were designed for ten microsatellites, from which four had the PCR conditions optimized. The microsatellites isolated in this study will be used to evaluate the genetic variability of Brazilian populations of river buffalo and to the gene mapping program established for this specie.

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