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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.
231

Prevalência e diversidade de beta-papilomavírus em amostras anogenitais e orais de homens do estudo HIM / Prevalence and diversity of beta-papillomavirus in anogenital and oral samples of males from the HIM study

Emily Montosa Nunes 18 May 2016 (has links)
O papilomavírus humano (HPV) é transmitido principalmente através do contato sexual e a infecção por estes vírus está fortemente associada ao desenvolvimento de tumores do colo do útero, da vulva e do ânus em mulheres, câncer do pênis e do ânus em homens, assim como tumores da cabeça e pescoço em ambos os sexos. Também há estudos em andamento para estimar a proporção de câncer de pele não-melanoma que podem ser atribuíveis às infecções por tipos virais pertencentes aos ramos cutâneos da filogenia do HPV. Os beta- (beta-) HPV vem sendo predominantemente isolados de tecidos cutâneos e sugere-se que façam parte da flora comensal humana. Entretanto, pouco se sabe sobre o papel destes nos sítios de detecção, seja em indivíduos imunosuprimidos como imunocompetentes. A fim de compreender a história natural dos HPV em homens, o Estudo da Infecção por HPV em homens (HIM Study) foi desenhado e conduzido entre 2005 e 2013 no Brasil, México e Estados Unidos (EUA). Em sua primeira triagem de amostras genitais, observou-se que 14,7% eram positivas para HPV, entretanto não correspondia a nenhuma das 37 sondas tipo-específicas para detecção dos principais beta- HPV. Após um protocolo de PCR fazendo uso de iniciadores genéricos, seguido por sequenciamento, observou-se um elevado número de tipos virais cutâneos nessas amostras. Perante isso, os objetivos deste trabalho foram (1) Determinar a prevalência de 43 tipos de beta-HPV em 729 homens participantes do estudo HIM que forneceram amostras anogenitais e orais em mesma visita de seguimento; (2) Identificar fatores demográficos e sexuais independentemente associados com a detecção de DNA destes tipos de HPV nos diferentes sítios anatômicos analisados. Para atingi-los, utilizou-se a metodologia Luminex atualmente bem estabelecida para genotipagem de beta-HPV. Dentre os homens genotipados, 557 (77,7%), 389 (54,3%) e 210 (29,3%) foram positivos para algum tipo de beta-HPV no região genital, do canal anal e da cavidade oral, respectivamente. Os tipos de beta-HPV mais prevalentes foram HPV-21, -22, -24 e -38 em todos os sítios anatômicos. Homens residentes no EUA (OR = 0,55, 95% intervalo de confiança [IC] de 0,38-0,80) e Brasil (OR = 0,49, 95% CI 0,33-0,73) foram significativamente menos propensos a serem detectados com algum beta-HPV no canal anal, comparado aos residentes no México. A idade foi marginalmente associada à maior prevalência de HPV na região do canal anal sendo que de homens mais velhos (31-44 anos, OR = 1,30, 95% CI 0,93-1,82; 45-70 anos, OR = 1,59, 95% CI 0,98-2,58) foram mais propensos a serem positivos para DNA de beta-HPV, comparado a homens mais jovens (18-30 anos). A prevalência de algum beta-HPV na cavidade oral também foi significativamente associada ao país de residência e idade. Fumantes (OR = 0,50, 95% CI 0.32-0.80) foram significativamente menos propensos a serem positivos para beta-HPV na cavidade oral do que os homens que nunca fumaram. A ausência de associação entre a detecção de beta-HPV e comportamentos sexuais específicos sugere o contato digital e auto-inoculação como rotas alternativas de transmissão desses vírus / HPV is primarily transmitted by sexual contact and infection by these viruses is strongly associated with the development of tumors in the cervix, vulva and anus in women, cancer of the penis and anus in men, as well as tumors in the head and neck in both genders. There are also ongoing studies ongoing to estimate the proportion of nonmelanoma skin cancer that may be attributable to infection by viral types from cutaneous branches of the phylogeny of HPV. Human beta papillomaviruses (beta-HPV) have been predominantly isolated from cutaneous tissues, and are thought to be part of the commensal flora. However, the role of beta-HPV detection in these sites is unknown, whether in immunosuppressed or immunocompetent individuals. In order to understand the natural history of HPV in men, the HPV Infection in Men Study (HIM Study) was designed and conducted between 2005 and 2013 in Brazil, Mexico and the United States (US). In a first screening of genital samples, it was observed that 14.7% were positive for HPV, but did not correspond to neither 37 type-specific probes for detection of major ?-HPVs. After a PCR protocol using of generic primers followed by sequencing, we observed a large number of cutaneous HPV types in these samples. For this reason, the objectives of this study were (1) To determine the prevalence of 43 types of beta-HPV in 729 male participants of the HIM study provided anogenital and oral samples in the same follow-up visit; (2) To identify demographic and sexual factors independently associated with DNA detection of these types of HPV in different anatomical sites analyzed. To achieve these objectives we used the currently well-established Luminex methodology for beta-HPV genotyping. Overall, 557 (77.7%), 389 (54.3%) and 210 (29.3%) men were positive for any beta-HPV type at the genital, anal canal and oral cavity, respectively. The most prevalent beta-HPV types were HPV-21, -22, -24 and -38 within all anatomic sites. Men from the US (OR= 0.55, 95% Confidence Interval [CI] 0.38-0.80) and Brazil (OR=0.49, 95% CI 0.33-0.73) were significantly less likely to have any beta-HPV at the anal canal than men from Mexico. Age was marginally associated with anal HPV prevalence with older men (31-44 years, OR=1.30, 95% CI 0.93-1.82; 45-70 years, OR=1.59, 95% CI 0.98-2.58) being more likely to have any beta-HPV at the anal canal compared to younger men (18-30 years). Prevalence of any beta-HPV at the oral cavity was also significantly associated with country of origin and age. Current (OR=0.50, 95% CI 0.32-0.80) smokers were significantly less likely to have beta-HPV at the oral cavity than men that never smoked. Lack of associations between beta- HPV detection and specific sexual behaviors suggests digital contact and autoinoculation as surrogate routes of transmission of these viruses
232

Desenvolvimento de estratégia de genotipagem para discriminação de alelos antitéticos do sistema de grupo sanguíneo Diego utilizando pool de DNA / Development of genotyping strategy for discrimination of antithetical alleles of the Diego blood group system using DNA pool

Thiago Vianna de Carvalho 07 May 2018 (has links)
Nesta dissertação, foi proposto o desenvolvimento de uma metodologia molecular por PCR em tempo real (qPCR) utilizando pool de DNA para a detecção de alelos que codificam antígenos importantes do sistema de grupo sanguíneo Diego. Esta ferramenta molecular será útil uma vez que são escassos os reagentes sorológicos para detecção desses antígenos e, quando existem, não permitem uma investigação em larga escala devido à pouca confiabilidade e alto custo. O sistema Diego (DI) possui 22 antígenos, sendo o antígeno Diª mais importante na prática transfusional. Eles são carreados pela proteína da Banda 3 que é proteína mais abundante na s hemácias, com 106 cópias. O antígeno possui uma maior prevalência, em indígenas americanos e asiáticos (6%-52%), já que é considerado um marcador antropológico de ancestrais mongóis; no entanto, a incidência desse antígeno tem aumentado dentre outras populações, como em caucasianos e afrodescendentes, e detectado em doadores de sangue, o que pode resultar em aloimunização de pacientes e dificultando o seu manejo terapêutico. Em contrapartida, a frequência do antígeno Dib em todas as populações é extremamente alta (>99,99%) e encontrar o raro fenótipo Di (a+b-) é ainda mais laborioso do que a busca pelo antígeno Diª. Sabe-se ainda muito pouco sobre a frequência dos antígenos Wrª e Wrb nas diferentes populações, mas estimase que a prevalência seja de 0,01% e >99,99% respectivamente. Foram utilizadas 410 amostras de doadores de sangue e 230 amostras de pacientes para genotipagem em qPCR utilizando pool de DNA para detecção dos alelos DI*01, DI*02, DI*02.03 e DI*02.04. A amplificação individualizada foi realizada quando a reação com pool demonstrou a amplificação de um dos alelos de interesse, DI*01 ou DI*02.03. Procedeu-se também com a clonagem dos alelos após à amplificação com as amostras controle, porém, ocorreu somente a clonagem dos alelos DI*02 e DI*02.03. Os fragmentos clonados apresentaram amplificação excelente e serão utilizados como controle positivo em testes moleculares futuros. Não foi possível a clonagem do DI*01 pelo problema da zigozidade da amostra controle. Houve 100% de concordância entre o resultado da genotipagem e as informações de fenotipagem das amostras controle. O alelo DI*01 ocorreu em 0,6% dos doadores de sangue e 1,7% em afrodescendentes, que corresponde a uma frequência genotípica DI*01/DI*02 de 1,2% e 1,3% respectivamente. Procedeu-se com as análises estatísticas comparativas entre o resultado desta pesquisa e de outras na população brasileira sobre os diferentes genótipos para entender se havia uma diferença estatística considerável. Ainda que a frequência para o genótipo DI*01/DI*02 seja mais baixa em doadores e mais alta em afrodescendentes do que o publicado em outros trabalhos brasileiros, a análise dos dados demonstrou que não havia diferença estatística com a maioria deles. A incidência aumentada do alelo DI*01 na população afrodescendente demonstra o aspecto da miscigenação. Conclui-se que a metodologia proposta funciona e tem aplicabilidade imediata em doadores de sangue e na busca de fenótipos raros. A incidência do alelo para Diª em doadores de sangue está abaixo do que um estudo anterior detectou em Ribeirão Preto (COZAC, 2004), que pode ser explicado pelas diferenças no censo populacional entre os estudos e pela coleta de amostra de universitários (62%). Não foram encontrados os genótipos DI*01/DI*01, DI*02.03/DI*02.03 e DI*02.03/DI*02.04 nas populações estudadas. / This work proposed the development of a molecular methodology by Real Time-PCR (qPCR) using DNA pool for the detection of alleles that encode important antigens of the Diego blood group system. This molecular tool will be useful since the serological reagents for the detection of these antigens are scarce and, when they exist, do not allow a large scale investigation due to the low reliability and high cost. The Diego (DI) system has 22 antigens, the Diª antigen is the most important in transfusion practice. They are carried by the Band 3 protein which is the most abundant protein on the erythroid surface, about 106 copies. The antigen has a higher prevalence in american indians and asians (6%-52%), since it is considered an anthropological marker of Mongolian ancestors; however, the incidence of this antigen has increased among other populations, such as in caucasians and afrodescendants, and detected in blood donors, which may result in alloimmunization of patients and make difficult their therapeutic management. In contrast, the frequency of Dib antigen in all populations is extremely high (>99.99%) and finding the rare phenotype Di (a+b-) is even more laborious than the search for Diª antigen. The frequency of Wrª and Wrb antigens in different populations is not well-known, but it is estimated that the prevalence is 0.01% and >99.99% respectively. 410 blood donor samples and 230 patient samples were used for genotyping in qPCR using DNA pool to detect the alleles DI*01, DI*01, DI*02.03 and DI*02.04. The single amplification was performed when the pool reaction demonstrated the amplification of one of the alleles of interest, DI*01 or DI*02.03. The alleles were also cloned after the control samples amplification. Only the cloning of the DI*02 and DI*02.03 alleles occurred, they presented excellent amplification and will be used as positive controls in future molecular tests, it was not possible to clone DI*01 by the control sample zygosity though. There was 100% agreement between the genotyping results and the phenotype information of the control samples. The DI*01 allele occurred in 0,6% of the blood donors and 1,7% in afrodescendants, which corresponds to a genotypic frequency DI*01/DI*02 of 1,2% and 1,3% in respectively. The comparative statistical analyzes between this research results and others in the Brazilian population on the different genotypes was performed to understand if there was a considerable statistical difference. Although the frequency of the genotype DI*01/DI*02 is lower in donors and higher in afrodescendants than that published in other Brazilian studies, data analysis showed that there was no statistical difference with most of them. The increased incidence of the DI*01 allele in the afrodescendant population demonstrates the aspect of miscegenation. It is concluded in this work that the proposed methodology works and has immediate applicability in the screening of blood donors and search for rare phenotypes. The incidence of the allele encoding Di ª antigen in blood donors is below than previously detected in Ribeirão Preto (COZAC, 2004), which can be explained by the differences in the population census between the studies and by the sample collection of university students (62%). The genotypes DI*01/DI*01, DI*02.03/DI*02.03 and DI*02.03/DI*02.04 were not found in the populations studied.
233

Prévention, contrôle et maîtrise du risque d’aspergillose invasive au Groupement Hospitalier Edouard Herriot lors de travaux : apport de la surveillance et de l’alerte environnementale et épidémiologique / Prevention, control and management of inavsive aspergillosis at Edouard Herriot hospital : contribution of enviropnmental-clinical surveys and alert systems

Loeffert, Sophie 20 November 2017 (has links)
Lors de travaux, la mise en suspension des spores d’Aspergillus constitue un facteur de risque reconnu dans le développement d’une aspergillose invasive. Durant l’année 2015, un pavillon de 6000 m2 (60 lits) de notre établissement a été entièrement déconstruit. L’objectif principal de cette étude a été d’évaluer l’association entre la concentration des spores d’Aspergillus fumigatus (AF) dans l’environnement extérieur et intérieur des pavillons, mais également avec la coexistence de cas cliniques, afin de proposer des recommandations d’amélioration (pratiques & techniques). Pour cela, durant 11 mois, une surveillance prospective de la contamination à Aspergillus fumigatus (AF) de l’air extérieur et intérieur par impaction sur gélose, mais aussi une investigation épidémiologique des patients à risque ont été mis en place. Au total, 3885 prélèvements d’air ont été réalisés (1744 extérieurs et 2141 intérieurs) permettant, par calcul des ratios de contamination (extérieurs vs intérieurs), de confirmer une efficacité des mesures de précautions pour réduire l’aérocontamination. Des prélèvements extérieurs continus des spores d’Aspergillacées (spore/m3/jour) ont également été réalisés par un capteur Hirst. Ce capteur, mais aussi le suivi des conditions météorologiques se sont révélés être des systèmes d’alerte utiles pour prévenir les pics de contamination. Enfin, 394 (383 environnementaux, 11 cliniques) isolats d’AF sensibles aux antifongiques ont été génotypés (MLVA). L’analyse des génotypes a montré 7 génotypes similaires entre des isolats d’AF cliniques et environnementaux confirmant un rôle de l’environnement hospitalier dans l’infection ou la colonisation des patients / Invasive aspergillosis (IA) due to Aspergillus has been associated with building construction, which may increase spores emission nearby immunocompromised patients. In 2015, one blocks of 6,000 m2 (60 beds) form our hospital has been entirely demolished. The aim of this study was to evaluate possible association between concentration of A. fumigatus (AF) spores in the outdoor and indoor environment and also with the clinical cases in order to propose some improvements in actuals methods and practices. A daily surveillance of fungal contamination was implemented during 11-months. Environmental survey was realized by air samplings, outdoor and indoor, with an automatic agar sampler. In parallel, surveillance of IA infection cases was conducted by epidemiological investigation. A total of 3885 air samples (1744 outdoor samples and 2141 indoor samples) were collected, allowing calculation of ratios (outdoor vs indoor) to confirm efficacy of preventives measures applied to reduce indoor aerocontamination. Outdoor continuous sampling of Aspergillaceae spores (spore/m3/day) was also realized by a Hirst collector. This collector was useful as alarm system to detect contamination peaks. Similarly, monitoring of meteorological parameters seems to be an interesting tool, to prevent Aspergillus peaks. Finally, 394 isolates of AF, susceptible to antifungals (383 environmental and 11 clinical isolates) were genotyped using MLVA. Analysis of genotypes showed 7 similar genotypes shared by environmental and clinical isolates, suggesting that clinical colonization and/or infection may originate from the hospital environment
234

Detection of Chlamydia trachomatis and Mycoplasma genitalium by genetic and serological methods

Jurstrand, Margaretha January 2006 (has links)
Chlamydia trachomatis infections are associated with a spectrum of clinical diseases including urethritis, prostatitis and epididymitis among men and cervicitis and pelvic inflammatory disease (PID), with an increased risk of infertility and ectopic pregnancy (EP), among women. In the search for other pathogens causing urethritis, Mycoplasma genitalium was isolated from urethral specimens from two men with acute urethritis (1980). Mycoplasma bacteria are extremely difficult to isolate by culture, and clinical studies have been possible only after the advent of the first PCR-based detection method. M. genitalium has been found to be associated with lower genital tract infections in both men and women. Finding evidence for a connection between M. genitalium and upper genital tract infections in women is still of major importance. The aim in papers I and II was to develop a PCR method for genetic characterization of clinical C. trachomatis isolates by sequence analysis of the omp1 gene, and to study the distribution of genotypes within sexual networks and determine if genotyping would improve partner notification. The method was used to determine the genotypes of C. trachomatis in 237 positive urogenital and/or urine specimens from men and women attending the STDClinic in Örebro during one year. Sequence analysis of the omp1 gene revealed that the most prevalent genotypes corresponded to C. trachomatis serovar E (47%), followed by F (17%), and K (9%). There were 161 networks found and specimens were sequenced from at least two patients in 47 networks. In seven of these 47 networks there were discrepant genotypes. In the largest network comprising 26 individuals two different C. trachomatis genotypes were found, and one partner had urethritis due to a Mycoplasma genitalium infection but was C. trachomatis negative. The need for a new method for M. genitalium DNA detection was one reason for study III. An existing conventional PCR protocol for detection of M. genitalium DNA was further developed into a real-time PCR (RT-PCR) with hybridisation probes. In order to evaluate the RT-PCR assay with clinical material, specimens from 398 men and 301 women attending the STD Clinic in Örebro were analysed, using the RT-PCR assay, and also by the well established conventional PCR in Copenhagen. Using the conventional PCR method as “gold standard”, the sensitivity for the RT-PCR assay was 72.2% and 68.2% and the specificity was 99.7% and 98.6%, respectively, in urogenital specimens from men and women. The aim in paper IV was to adapt a Triton X-114 extracted Lipid-Associated Membrane Protein (LAMP) Enzyme Immuno Assays (EIA) method to detect antibodies against M. genitalium and to evaluate the association between M. genitalium and PID and EP, using sera sampled in Örebro during the 1980s, and also to compare the number of sera having M. genitalium antibodies against those having C. trachomatis antibodies, using a commercial anti- Chlamydia trachomatis EIA assay. No statistical significant association could be demonstrated between M. genitalium antibodies and PID or EP in our serum material. However, a slight trend toward association was found when focusing on younger individuals. Antibodies against C. trachomatis were found to be significantly associated with PID and EP.
235

Water storage in rural households : intervention strategies prevent waterborne diseases

Potgieter, Natasha 11 December 2007 (has links)
Poor sanitation, unhygienic practices and close living associations between people and animals in rural communities increase the risk of zoonoses and add to faecal contamination of stored drinking water. Point-of-use interventions can improve the microbiological quality of household drinking water and a combination of microbial and chemical indicator tests could identify the origin of faecal pollution. The improvement of the microbiological quality of drinking water in rural households by the implementation of intervention strategies which included the use of traditional storage containers as well as an improved safe storage container (CDC, USA), with or without the addition of a sodium hypochlorite solution were determined. The origin of faecal contamination in the water sources and household stored water were determined using male specific F-RNA subgroup genotyping. This study attempted to assess the survival of indicator microorganisms and selected bacterial pathogens and viruses in the improved safe storage container in borehole and river water samples. An intervention study was conducted in two rural villages utilising different source water. Results indicated that the improved safe storage container without the addition of a stabilized sodium hypochlorite solution did not improve the microbiological quality of the stored drinking water and had counts of indicator microorganisms similar to that found in the traditional storage containers. However, the households using the 1% and the 3.5% sodium hypochlorite solutions have shown an effective reduction in the counts of indicator microorganisms in both the traditional and the improved safe storage containers. The compliance with the use of the sodium hypochlorite interventions ranged between 60% and 100%, which was in agreement with similar studies carried out in other developing countries. One village complied with the intervention while the other village did not. Reasons for this included financial factors, an unsupportive infrastructures and lack of education and knowledge on health risks by the households. Male specific F-RNA bacteriophage genotyping showed that faecal contamination in the water source samples and both the traditional and improved safe storage containers at the point-of-use were primarily of animal origin (Subgroup I). Households using river water had subgroup II F-RNA bacteriophages present in the stored household water, which was associated with human faecal pollution. However, subgroup II F-RNA bacteriophages has been isolated from faeces of cattle and poultry, which indicated that F-RNA subgroup typing might not be a specific tool to determine the origin of faecal pollution in water sources. Laboratory seeding experiments indicated that 1% sodium hypochlorite solution were less effective in reducing heterotrophic bacteria, Escherichia coli, Salmonella typhimurium, Clostridium perfringens, F-RNA bacteriophages and coxsackie B1 virus counts in the improved safe storage containers filled with river water with a high turbidity. However, the 1% sodium hypochlorite solution did reduce the indicator and seeded microorganisms within 60 min in containers filled with borehole water with a low turbidity. The 3.5% sodium hypochlorite solution effectively decreased the numbers of microorganisms to undetectable limits within 60 min in both the borehole and river filled storage containers irrespective of the turbidity values. This study has showed that a combination of intervention strategies can provide rural communities with microbiologically safe drinking water. / Thesis (PhD (Medical Virology))--University of Pretoria, 2008. / Medical Virology / PhD / unrestricted
236

Intérêt majeur de l'identification de biomarqueurs prédictifs dans la chimiothérapie des cancers / Identification of predictive biomarkers in cancer chemotherapy

Vataire, Anne-Lise 17 December 2014 (has links)
Le cancer est un problème de santé publique majeur et représente l'une des principales causes de décès dans le monde. Il représente ainsi un lourd fardeau humain et économique pour la société. Au cours de ces dernières années, l'innovation technologique avec notamment le séquençage d'acide désoxyribonucléique (ADN) a modifié la vision et la pratique de la cancérologie en proposant de sélectionner le traitement médical le plus approprié aux caractéristiques génotypiques de chacun. Dans certains types de cancer, la chimiothérapie est parfois prescrite abusivement avec de possibles effets délétères importants à long terme. La prescription de la chimiothérapie ne doit donc pas se faire de manière systématique et l'identification de biomarqueurs prédictifs de la réponse au traitement devient donc une étape cruciale. En effet un grand nombre de biomarqueurs voire des combinaisons de biomarqueurs doivent être testés afin d'identifier les patients susceptibles de bénéficier de la chimiothérapie. A cet effet, des analyses statistiques spécifiques à l'analyse de la mutation TP53 dans le cancer du poumon non à petites cellules ont été mises en place dans la première partie de cette thèse. Enfin, la seconde partie de cette thèse porte sur l'évaluation médico-économique de ces tests, primordiale pour le financement de ces innovations et donc pour avoir un impact direct sur les patients atteints de cancer. Nos résultats ont démontrés que bien que ces tests peuvent être coût-efficaces et recommandés dans plusieurs pays, leurs utilisations en France restent limitées en raison de l'absence de remboursement / Cancer is a leading cause of death around the world and thus a major worldwide public health problem and a heavy human and economic burden. In recent years, the practice of cancer medicine has evolved with technological innovation such as deoxyribonucleic acid (DNA) sequencing which allows the selection of the most suited treatment for each genotypic characteristic. With chemotherapy, a treatment with potentially significant long-term adverse effects, being overprescribed in some types of cancer, the identification of a predictive biomarker of response to treatment became a crucial step. Indeed a large number of biomarkers or combinations of biomarkers have to be tested to identify patients likely to benefit from chemotherapy and thus to avoid the systematic prescription of chemotherapy. Accordingly, the first part of this thesis focused on the specific statistical analysis of TP53 mutations in non-small cell lung cancer. The second part of this thesis’ aim was to study the medico-economic evaluation of these tests, since these evaluation are essential for these test’s financing. Results showed that although the tests may be cost-effective and recommended in several countries, their uses in France were limited due to the lack of reimbursement
237

Estratégias de imputação de genótipos de marcadores SNP para estudos de associação genômica em animais da raça Nelore / Strategies of genotypes imputation for genome-wide association studies in Nellore cattle

Fabiane de Lima Silva 07 November 2013 (has links)
Temperamento em bovinos é definido como a reação dos animais em resposta ao contato com o ser humano, geralmente atribuído ao medo ocasionado no manejo. Animais agitados são mais difíceis de manejar nas fazendas. Estudos na literatura mostram que características de temperamento influenciam o desempenho produtivo dos rebanhos, devido à sua correlação com outras características dentre elas, ganho de peso diário, taxa de prenhez, qualidade e rendimento de carcaça. Todavia, estudos visando o melhor entendimento dos mecanismos biológicos, e da arquitetura genética destas características são escassos. Com a evolução das tecnologias de genotipagem em alta densidade com marcadores de polimorfismo único (SNP), observou-se um aumento de pesquisas nas áreas de seleção genômica (GS) e associação genômica (GWAS). Entretanto, devido ao alto custo que a genotipagem em larga escala apresenta, torna-se inviável a genotipagem para todos os animais candidatos à seleção. Porém, existe a possibilidade de utilizar painéis de baixa densidade de SNP e inferir estes genótipos desconhecidos para painéis de alta densidade. Neste contexto foram desenvolvidos dois estudos. No primeiro, o objetivo foi identificar regiões cromossômicas associadas com características de temperamento em animais da raça Nelore. As características avaliadas foram: velocidade de saída (VS) e mediana do escore composto (EC_mediana), em que 599 e 575 animais foram utilizados, respectivamente. Todos os animais foram genotipados com Illumina BovineHD BeadChip (800K), e para o GWAS dois modelos estatísticos foram aplicados. O primeiro modelo utilizado foi genômico de única etapa (ssGBLUP), em que os efeitos dos SNP são derivados da predição dos valores genéticos genômicos dos animais. O segundo modelo foi linear misto, similar ao modelo anterior, porém várias análises, SNP por SNP (regressão simples) foram realizadas. Nos dois modelos foram incluídos os efeitos de grupo de contemporâneo como fixo, idade do animal como covariável e efeito poligênico do animal e ambiente permanente como aleatórios. Os componentes de variância foram estimados pelo método de máxima verossimilhança restrita. Os coeficientes de herdabilidade apresentaram baixa magnitude com estimativas de 0,02 e 0,05 para VS e EC_mediana, respectivamente. Diferentes regiões cromossômicas foram associados com as características estudadas nesta população, de acordo com os modelos utilizados, contribuindo para o entendimento da arquitetura genética dessas características. No segundo, o objetivo foi avaliar a acurácia de imputação também nesta população, usando dois painéis de baixa densidade (3K e 6K) e um de média densidade (50K) imputados para o painel de alta densidade (800K). Os animais genotipados com 800K foram divididos em população de validação e população de referência. Na população de validação, os animais tiveram seus genótipos mascarados para os chips Illumina 3K, 6K e 50K. A imputação de 3K, 6K e 50K para 800K foi realizada utilizando os softwares de imputação fastPHASE e Beagle. O software fastPHASE apresentou maiores valores de acurácia de imputação em comparação ao Beagle. O painéis 6K e 50K apresentaram maiores valores de acurácia. / Temperament in cattle is generally defined as the reaction of an animal in response to contact with human, usually attributed to the fear. Animals agitated are harder to manage in farms. Studies in the literature reported that temperamental traits have been found to influence the productive performance of herds, due to its correlation with other traits such as carcass quality, daily gains, pregnancy rate and feed efficiency. However, almost nothing is known regarding the genetic landscape controlling temperamental animal variation in cattle. With the advances in genotyping technologies for high density genotyping platforms to markers of single nucleotide polymorphisms (SNP), there was an increase in research in the areas of genomic selection (GS) and genome-wide association studies (GWAS). However, genotyping many animals with a high-density marker panel can be expensive and economically unfeasible. An alternative in this context is to use a lower density marker panel on a larger number of animals, and impute the missing genotypes. In this context two studies were developed. In the first study, the objective was to identify chromosomal regions associated with temperament traits in Nellore cattle. The temperamental traits evaluated in this study were: exit velocity (VS) and the median score temperament (EC_mediana) assessed in 599 and 575 animals, respectively. All animals were genotyped with Illumina BeadChip BovineHD (800K), and two GWAS statistical models were applied. The first model used was genomic single step (ssGBLUP) in which the effects of SNP are derived from the genomic prediction values of the animals. The second was linear mixed model, similar to the previous model, but a series of models, one for each SNP (single regression), were performed. In both models were included the effects of contemporary group as fixed, the animal\'s age as a covariate effect and polygenic animal and permanent environment as random effect. Variance components were estimated by restricted maximum likelihood. The heritability coefficients showed low magnitude estimative of 0.02 and 0.05 for VS and EC_mediana, respectively. Different chromosomal regions were associated with the traits studied in this population, according with the models used, and moreover to contribute in the understanding of the genetic architecture of these traits. In the second study, the objective was to evaluate the accuracy of imputation in a same population, using two panels of low-density (3K and 6K) and one medium-density (50K) panel markers imputed up to higher density of 800K. The animals genotyped with 800K markers panel were split into a reference population and validation population. The validation population the animals had markers masked to Illumina chip 3K, 6K e 50K. Imputation from 3K, 6K and 50K up to 770K markers was performed using fastPHASE and Beagle. The software fastPHASE had higher imputation accuracy compared to Beagle. The 6K and 50K panels showed higher accuracy.
238

Like a Rolling Circle : Developing in-situ genotyping of chromosomal barcodes in the DuMPLING method

Svahn, Fabian January 2021 (has links)
DuMPLING is a newly developed high-throughput method to study singlecellphenotypes in a pooled and barcoded library using a microfluidicchip. The chip enables parallel biophysical measurements of singlecells, after which in-situ genotyping connects the cells to a certainstrain of the library. The method has been previously applied with abarcoded library, where genotyping was performed on barcodes presenton high copy number plasmids. In this project, I apply and developthe Rolling Circle Amplification method to amplify the signal frombarcodes present on the E. coli chromosome. A small librarycontaining three different chromosomal barcodes is investigated. Veryhigh efficiency of signal generation is achieved for the firstbarcode, good efficiency is achieved for the second, and no signal isachieved for the third. Genotyping is also successfully performed ona strain with two different barcodes present on the chromosome. Thegenotyping method described herein can be applied to screen foradditional barcodes that may be incorporated in a larger library thatin turn can be used to ask important biological questions, forexample using the high throughput DuMPLING method.
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Contribution des variations structurales de type insertions/délétions à l'adaptation, la variation des caractères et les performances hybrides chez le maïs / Contribution of insertions/deletions-type structural variations to adaptation, phenotypic variation and hybrid performances in maize

Mabire, Clément 23 April 2019 (has links)
Le récent développement des méthodes de séquençage permet aujourd’hui d’identifier des variations structurales chez de nombreuses espèces. Chez le maïs, des milliers de grandes insertions et délétions (InDel) de quelques pb à plusieurs centaines de Kbp ont été découvertes entre le génome de référence B73 et de nombreux autres génomes reséquencés. Ces InDel peuvent changer la composition des gènes entre les individus et donc être impliquées dans la variation du phénotype, mais cet effet sur le phénotype reste mal connu. L’objectif de cette thèse était d'étudier la contribution des InDel à l'adaptation, aux variations phénotypiques et aux performances hybrides chez le maïs. Nous avons développé une puce de génotypage des InDel Affymetrix® Axiom® capable de génotyper 105 927 InDel de 35bp à 129,7Kbp. 79 969 de ces InDel ont leur séquences absentes du génome de référence B73 et ont été identifiées par l’assemblage 3 génomes (F2, C103, and PH207). Nous avons sélectionné 61 492 InDel polymorphiques pour génotyper 362 lignées de maïs représentant une large gamme de diversité pour étudier la contribution des InDel à la diversité génétique, l’adaptation et la variation des caractères. Nous avons également génotypé 1 million de SNP à partir de deux puces de génotypage et du génotypage par séquençage pour étudier la complémentarité entre les InDel et les SNP. Qu’ils soient calculés avec les InDel ou les SNP la structuration génétique et les valeurs d’apparentement entre les lignées sont très similaires, ce qui suggère que la plupart des InDel ont suivi la même trajectoire évolutive que les SNP. 51% des InDel ne sont pas en déséquilibre de liaison élevé (>0.8) avec aucun SNP proche donc l’effet de ces InDel n’est donc a priori pas capturé pas des SNP à cette densité. Parmi les 294 régions génomiques associées au phénotype (QTL), 13 nouveaux QTL ont été détectés grâce aux InDel par rapport aux SNP par une approche de génétique d’association (GA). Nous avons détecté un enrichissement en InDel sous sélection entre les lignées tropicales, cornées et dentées par rapport aux SNP, avec 56 sur 188 régions sous sélection détectées avec les InDel. Ces régions contiennent des gènes impliqués dans l’adaptation et/ou la tolérance aux stress. De plus, le plus grand nombre d’associations a été découvert pour la floraison, caractère adaptatif chez le maïs. Ces résultats suggèrent que les InDel sont plus souvent impliquées dans l’adaptation et la tolérance aux stress. Nous avons enfin testé l’effet des InDel sur les performances hybride en analysant un panel de 287 hybrides issus du croisement de 210 lignées tempérées du panel précédent. Nous avons décomposé la variance des performances hybrides en distinguant les effets de dominance et d’additivité pour la floraison femelle (FF), la hauteur (PH) et le rendement (GY). La plus forte part de dominance et d’interaction génotype-environnement a été observée pour le GY et la plus faible pour la FF. L’effet additif et de dominance de 51,844 InDel et 469 267 SNP a été testé pour 4 combinaisons d’environnements par une approche de GA. 78 et 133 QTL avec un effet additif et dominant respectivement ont été identifiés, dont 6 et 11 avec des InDel. 83% de ces QTL ont été identifiés dans une seule combinaison d’environnements. Un des QTL de rendement identifié avec des InDel est situé dans un large cluster d’InDel sur le chromosome 6 et colocalise avec un QTL déjà identifié avec des SNP avec un effet fort dans l’augmentation du rendement sous des températures élevées. L’ajout de l’effet de dominance en plus de l’effet additif permet d’augmenter la précision des prédictions génomiques jusqu’à 5,6% pour le rendement. Cependant, l’ajout du génotypage des InDel en plus de celui des SNP n’a pas permis d’améliorer les prédictions des phénotypes hybrides. / In the last decades, the rapid development of genome sequencing allowed to identify structural variations in many species. In maize, thousands of large insertions and deletions (InDels) from few bp to hundreds of Kbp were discovered by comparing the reference genome B73 and many other resequenced genomes. These InDel sequences can carry genes and therefore be involved in phenotypic variation by changing the gene composition between individuals, but their effect on phenotype was not well studied. The aim of this thesis was to study the contribution of InDels to adaptation, phenotypic variations and hybrid performances in maize. We developed an Affymetrix® Axiom® genotyping array that allowed to genotype 105,947 InDels sequences ranging from 35bp to 129,7Kbp of size. 79,969 out 105,947 sequences of these InDels were not present in B73 reference genome and have been discovered by assembling three genomes (F2, C103, and PH207). We selected 61,492 polymorphic InDels to genotype a 362 maize inbred lines panel representing a broad range of diversity to study the contribution of InDels to genetic diversity, adaptation and trait variation. We also assembled one million of SNPs from two genotyping arrays and genotyping by sequencing to study the complementarity between InDels and SNPs. Genetic structuration and relatedness between inbred lines displayed by SNPs or by InDels were highly similar suggesting that almost all indels and SNPs followed a similar evolutionary trajectory. 51% of InDels were not in high linkage disequilibrium (LD>0.8) with any nearby SNP suggesting that the effect of these InDels was not be well captured using this density of SNP. Thanks to InDels, we detected 13 new quantitative trait loci (QTLs) among 294 QTLs identified for 23 traits by a genome wide association studies (GWAS). Similarly, 56 out 188 regions under selection between tropical, dent and flint maize lines were identified by InDels leading to an enrichment of genomic regions under selection detected by InDels compared to SNPs. These InDels include genes involved in tolerance to biotic and abiotic stress and/or adaptive traits as flowering time. Accordingly, the highest number of associated InDels was found for flowering time. These results suggest that InDels were often involved in adaptation and stress tolerance. In order to study the effect of InDels on hybrid performances, we analyzed a panel of 287 hybrids derived from the crossing of 210 maize temperate inbred lines from the previous panel. We decomposed the variance of female flowering (FF), plant height (PH) and grain yield (GY) by distinguishing the additive and dominant genetic effects. We observed the highest dominance and genotype by environment effects for GY and the lowest for FF. We performed GWAS on this panel by testing additive and dominance effects of 51,844 InDels and 469,267 SNPs on these three traits in 4 different environment combinations. We identified 78 and 133 QTLs with an additive and dominance effect, respectively including 6 and 11 QTLs discovered only by InDels. 83% of all QTLs were found with only one environment combination. One QTL for GY detected with InDels was located in a large cluster of InDels on chromosome 6, previously identified to have a strong effect on GY in heat conditions. We finally used InDels and/or SNPs genotyping to predict hybrid performances. Whereas including a dominance effect in genomic prediction models increased by 1.5 to 5.6% predictive abilities (PA) for GY, including InDels genotyping did not increased PA.
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Význam a funkce stromálních enzymů v patogenezi keratokonu / The role and function of stromal enzymes in keratoconus pathogenesis

Ďuďáková, Ľubica January 2015 (has links)
Lubica Dudakova Doctoral Thesis ABSTRACT Keratoconus (KC) is a non-inflammatory disease of the cornea, in which ectasia and thinning occur probably due to defects in the collagen fibers binding. It is one of the most common indications for corneal transplantation. KC is a complex disorder with the involvement of both genetic and environmental factors; however the exact pathogenic mechanisms leading to the disease development have not been elucidated. The main aim of our work was to compare the presence and enzyme activity of cross- linking enzymes lysyl oxidases (LOX and LOX-like enzymes), in control human cornea samples and explanted cornea gained from patients with KC. We also focused on diseases previously described to be associated with KC with the aim to identify common signs among them. Furthermore, we replicated association of single nucleotide polymorphisms (SNPs) in LOX and hepatocyte growth factor (HGF) with KC risk. We attempted to link all pathophysiological disturbances observed in KC into one common pathway. We have used a wide spectrum of methods (cell culturing, immunohisto- and immunocytochemistry, microscopy, fluorimetric enzyme activity measurement, genotyping and direct sequencing, statistical analysis). We demonstrated the presence of entire family of LOX enzymes in control and in KC...

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