• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 144
  • 133
  • 32
  • 12
  • 9
  • 4
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 382
  • 140
  • 70
  • 62
  • 57
  • 48
  • 47
  • 43
  • 43
  • 43
  • 41
  • 34
  • 33
  • 33
  • 30
  • 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.
251

Validação de Marcadores Inserção/Deleção para Genotipagem Fetal não Invasiva / Insertion/Deletion Markers Validation for non Invasice Fetal Genotyping

Ng, Ayling Martins 15 May 2015 (has links)
A presença de DNA fetal livre de células no plasma materno possibilitou o surgimento de novas tecnologias para o diagnóstico pré natal não invasivo. Existem técnicas de genotipagem fetal já estabelecidas em investigações de sequências exclusivas fetais, mas a sua aplicação para a identificação humana em testes de paternidade ainda é pouco conhecida. A metodologia de genotipagem fetal não invasiva foi padronizada com o uso de três lócus InDels e iniciadores inserção-específicos. Entretanto, para que se alcance o poder satisfatório, é necessário investigar elevado número de lócus informativos. Para suprir a ausência de informações suficientes sobre lócus deste tipo, são descritas, no presente trabalho, as condições laboratoriais para PCR e as frequências alélicas de um conjunto de lócus InDels, ainda inéditos, em uma amostra representativa da população urbana brasileira, visando aumentar a robustez e a confiabilidade da genotipagem fetal não invasiva na investigação de paternidade. Foram selecionados 20 lócus, um em cada cromossomo. Em um dos lócus polimórficos foi encontrado um alelo novo, não registrado no banco de dados do NCBI. O poder de discriminação e o poder de exclusão dos 16 lócus polimórficos combinados (0,999 e 0,937, respectivamente) tiveram valores dentro do esperado para um conjunto com essa quantidade de lócus bialélicos. Alguns lócus apresentaram elevado número de indivíduos que não responderam à amplificação, indicando a necessidade de reajustes na padronização dos procedimentos laboratoriais e a possibilidade de variabilidade das sequências complementares aos iniciadores empregados, o que exigirá o sequenciamento completo das regiões. Para a maioria dos lócus, entretanto, os parâmetros forenses atingiram valores esperados e sugerem que podem ser úteis na composição de painel robusto e eficiente para ser usado na genotipagem fetal não invasiva. / The presence of cell-free fetal DNA in maternal plasma allows for new non-invasive prenatal diagnosis technologies to develop. Even though there are already well-established fetal genotyping techniques in fetal-exclusive sequence investigations, their application to human identification in paternity tests is not yet well-known. Non-invasive fetal genotyping methodology was previously standardized using three InDel loci and insertion-specific primers. However, in order to attain satisfactory power, it is necessary to investigate large number of informative loci. To compensate for the absence of sufficient information about this type of locus, this work describes the PCR conditions and determinates allelic frequencies for a set of unpublished InDel loci, in a representative group of Brazilian population, raising the robustness and reliability of non-invasive fetal genotyping in paternity investigation. We selected 20 loci, one in each chromosome. Not previously registered on NCBI database allele was found in one of the polymorphic loci. Discrimination and exclusion power of the 16 polymorphic loci combined (0.999 and 0.937, respectively) had expected values for an ensemble with such an amount of biallelic loci. Some loci showed many non-amplified individuals, vincing the need of corrections in the standardizing process and the possible variability of the complementary sequences to the primers used. However, for most loci, the forensic parameters reached the expected values and suggest that they may be useful in the more robust panel for utilization in non-invasive fetal genotyping.
252

Genotipagem de linhagens de Yersinia spp. por high-resolution melting analysis / Genotyping of Yersinia strains by high-resolution melting analysis

Souza, Roberto Antonio de 23 May 2013 (has links)
O gênero Yersinia pertence à família Enterobacteriaceae e compreende 17 espécies. Y. pestis, Y. pseudotuberculosis e Y. enterocolitica são reconhecidamente patógenos de humanos e animais. Y. pestis cause a peste. Y. pseudotuberculosis e Y. enterocolitica são agentes causadores, sobretudo, de gastroenterites transmitidas por água e alimentos. As demais 14 espécies são, usualmente, consideradas não-patogênicas, com exceção de Y. ruckeri sorogrupo O:1 que causa infecções em peixes. Nas últimas décadas, a tipagem molecular tornou-se uma importante ferramenta nos estudos filogenéticos de numerosos micro-organismos e o desenvolvimento de sistemas de tipagem rápidos e baratos pode facilitar os estudos epidemiológicos de infecções bacterianas. No presente estudo objetivou-se desenvolver um método de genotipagem de Yersinia spp. baseado em high-resolution melting analysis (HRMA) para diferenciar os single-nucleotide polymorphisms (SNPs) presentes nas sequências dos genes 16S rRNA, glnA, gyrB, hsp60 e recA e aplicá-lo na tipagem de 40 linhagens de Y. pseudotuberculosis e 50 linhagens de Y. enterocolitica, bem como separar por HRMA as espécies Y. pseudotuberculosis e Y. enterocolitica. Os SNPs foram determinados nas sequências dos loci acima citados a partir de um conjunto de 119 linhagens de Yersinia spp. depositadas no GenBank/EMBL/DDBJ. Foram encontrados nas sequências dos genes analisados de Y. pseudotuberculosis, Y. enterocolitica, Y. bercovieri, Y. rohdei, Y. intermedia, Y. mollaretii e Y. ruckeri 10, 10, 9, 6, 4, 1 e 1 SNPs, respectivamente. Nenhum SNP foi encontrado nas sequências analisadas de Y. pestis e um grande número de SNPs foi encontrado nas sequências analisadas de Y. frederiksenii, Y. kristensenii e Y. massiliensis, o que impossibilitou a genotipagem dessas espécies por HRMA. As demais espécies não foram analisadas. Foram desenhados pares de primers para flanquear os SNPs encontrados em cada espécie de Yersinia testada. Usando um conjunto de primers espécie-específicos, a diversidade genética de cada espécie de Yersinia foi determinada por HRMA e a análise filogenética foi baseada na sequência concatenada composta pelos nucleotídeos identificados em cada fragmento analisado. O agrupamento foi realizado com o software BioNumerics usando o método UPGMA com 1.000 replicatas de bootstrap. A árvore filogenética ii construída para Y. pseudotuberculosis agrupou as linhagens em clusters bio-sorogrupo específicos. As linhagens do bio-sorogrupo 1/O:1 foram agrupadas em um cluster e as linhagens do bio-sorogrupo 2/O:3 em outro. A árvore filogenética construída para Y. enterocolitica agrupou as linhagens em três grupos. As linhagens altamente patogênicas, do biotipo 1B, foram agrupadas em um cluster, as linhagens de média patogenicidade, dos biotipos 2, 3, 4 e 5, foram agrupadas em um segundo cluster e as linhagens consideradas nãopatogênicas, do biotipo 1A, foram agrupadas em um terceiro cluster. O agrupamento encontrado em Y. pseudotuberculosis e Y. enterocolitica foi consistente com o perfil patogênico característico dessas duas espécies. Nenhuma correlação epidemiológica significativa foi encontrada no agrupamento de Y. bercovieri, Y. rohdei, Y. intermedia, Y. mollaretii e Y. ruckeri de acordo com os resultados de HRMA. Ademais, o método de HRMA aqui desenvolvido foi capaz de separar as espécies Y. pseudotuberculosis e Y. enterocolitica. O método de HRMA desenvolvido nesse estudo pode ser usado como uma alternativa para a genotipagem e para a diferenciação de Y. pseudotuberculosis de Y. enterocolitica. Esse método também pode complementar os métodos baseados em sequências e facilitar os estudos epidemiológicos dessas duas espécies de Yersinia. / The genus Yersinia belongs to the family Enterobacteriaceae and comprises 17 species. Y. pestis, Y. pseudotuberculosis and Y. enterocolitica are well recognized human and animal pathogens. Y. pestis causes plague. Y. pseudotuberculosis and Y. enterocolitica are, usually, causative agents of food-waterborne gastroenteritis. The other 14 Yersinia species are considered to be non-pathogenic, with the exception of Y. ruckeri serogroup O:1 which causes infections in fishes. In the last few decades, molecular typing has become an important tool in phylogenetic studies of several microorganisms and the development of fast and inexpensive typing systems can facilitate epidemiological studies of bacterial infections. The present study aimed to develop a method of Yersinia spp. genotyping based on high-resolution melting analysis (HRMA) in order to differentiate the single-nucleotide polymorphisms (SNPs) present in the 16S rRNA, glnA, gyrB, hsp60 and recA sequences and apply it in the typing of 40 Y. pseudotuberculosis strains and 50 Y. enterocolitica strains, as well as, to separate by HRMA the Y. pseudotuberculosis and Y. enterocolitica species. The SNPs were determined in the sequences of the aforementioned loci using a set of 119 Yersinia strains deposited in the GenBank/EMBL/DDBJ database. It were found in the gene sequences analyzed of Y. pseudotuberculosis, Y. enterocolitica, Y. bercovieri, Y. rohdei, Y. intermedia, Y. mollaretii and Y. ruckeri 10, 10, 9, 6, 4, 1 and 1 SNPs, respectively. No SNPs was found in the analyzed sequences of Y. pestis and a large number of SNPs were found in the analyzed sequences of Y. frederiksenii, Y. kristensenii and Y. massiliensis what prevented their genotyping by HRMA. The remaining Yersinia species were not analyzed. It was designed primer pairs to flank the SNPs found in each Yersinia species tested. Using a specie-specific set of primers, the genetic diversity of each Yersinia species used was determined by HRMA and the phylogenetic analysis was based on the concatenated sequence composed by the nucleotides identified in each fragment analyzed. Clustering was performed with the software package BioNumerics using UPGMA method and 1,000 bootstrap replicates. The phylogenetic tree constructed for Y. pseudotuberculosis grouped the strains into bio-serogroups specific clusters. The strains of 1/O:1 bio-serogroup were grouped into one cluster and the strains of 2/O:3 bio-serogroup into iv other cluster. The phylogenetic tree constructed for Y. enterocolitica grouped the strains in three clusters. The highly pathogenic strains, of biotype 1B, were grouped into one cluster, the moderate pathogenic strains, of biotypes 2, 3, 4 and 5, were grouped into a second cluster and, the non-pathogenic strains, of biotype 1A, were grouped into a third cluster. The clusterization of Y. pseudotuberculosis and Y. enterocolitica were consistent with the pathogenic profile characteristic of these two Yersinia species. No significant epidemiological correlation was found in the grouping of Y. bercovieri, Y. rohdei, Y. intermedia Y. mollaretii and Y. ruckeri according to HRMA results. Moreover, the HRMA-based method develop here was able to separate the Y. pseudotuberculosis and Y. enterocolitica species. The HRMA assay developed in this study can be used as an alternative for the genotyping and the differentiation of Y. pseudotuberculosis and Y. enterocolitica. This method can also complement sequence-based methods and facilitate epidemiological studies of these two Yersinia species.
253

Diversidade, estruturação genética e mapeamento associativo em germoplasma japonês de arroz utilizando marcadores DArT-seq / Diversity, genetic structuring and association mapping in Japanese rice germoplasm using DArT-seq markers

Rizzi, Vanessa 31 August 2017 (has links)
O conhecimento da diversidade genética e da estrutura populacional das variedades mantidas em bancos de germoplasma é de fundamental importância para sua efetiva utilização em programas de melhoramento. O mapeamento por associação, também conhecido como mapeamento por desequilíbrio de ligação, é um dos principais métodos para relacionar genes e alelos às características de interesse, através da co-segregação de marcadores genéticos polimórficos com os genes envolvidos na variação das características em estudo. O Banco de Germoplasma de Arroz do Departamento de Genética da ESALQ contém 192 acessos japoneses que foram estudados com o objetivo de entender sua diversidade, estruturação genética e determinar a associação genômica de caracteres agronômicos relacionados a produção de grãos. A caracterização molecular foi conduzida através da tecnologia DArT-seq, que gerou dados de marcadores SNPs (single-nucleotide polymorphism) e silico DArTs. Em seguida, após a filtragem, 5.578 SNPs de alta qualidade foram utilizados para calcular as estimativas de diversidade no pacote hierfstat e a estrutura do painel de acessos através da análise discriminante de componentes principais (DAPC), que consiste em determinar existência de cluster em um grupo de genótipos em que não há informação a priori sobre existência de grupos. A diversidade genética nos acessos foi evidenciada pelo valor de heterozigosidade esperada (HS) (0,0279) e a estruturação foi evidenciada pela formação de três subgrupos. O mapeamento associativo foi realizado com o uso do pacote GAPIT, sendo considerados seis caracteres: número de dias para florescimento (NDF), estatura de planta (EP), comprimento da panícula (CP), peso de parcela (PP), massa de mil grãos (MMG) e CICLO, bem como 24.266 marcadores silico DArTs e 1.965 marcadores SNPs. Foram detectadas um total de 113 associações significativas genótipo-fenótipo (P<0,001) quando utilizado marcadores silico DArTs em todas as seis características analisadas e, um total de 21 associações significativas genótipo-fenótipo (P<0,001) quando utilizado marcadores SNPs para apenas quatro das seis características analisadas: EP, CICLO, MMG e PP. Considerando-se os 113 silico DArTs associados significativamente na análise, 90 foram localizados em regiões intergênicas e 23 foram localizados dentro de genes. Enquanto que, dos 21 SNPs significativos, 11 foram localizados em regiões intergênicas e 10 foram localizados dentro de genes. A informação gerada neste estudo foi útil para testar associações ao longo do genoma do arroz. O modelo linear misto (MLM) empregado no mapeamento associativo acredita-se ter conseguido controlar eficientemente os falsos positivos no mapeamento utilizando os marcadores SNPs. As informações geradas neste estudo servem de base para avaliações mais aprofundadas, utilizando o conjunto de marcadores significativos como ponto de partida para determinação dos genes mais importantes para a produtividade em arroz. / The knowledge of the genetic diversity and population structure of varieties maintained in germplasm banks is crucial for their effective use in breeding programs. Association mapping, also known as linkage disequilibrium mapping, is one of the main methods for relating genes and alleles to the characteristics of interest, through the co-segregation of polymorphic genetic markers with the genes involved in the variation of the characteristics under study. The Rice Germplasm Bank of the Department of Genetics of ESALQ contains 192 Japanese accessions that were studied with the purpose of understanding its diversity, genetic structuring and determining the genomic association of agronomic traits related to grain production. The molecular characterization was conducted by DArTseq technology, which generated data of SNPs (single-nucleotide polymorphism) markers and silico DArTs. Then, after filtering, 5,578 high-quality SNPs were used to calculate the diversity estimates in hierfstat package and the accession panel structure through discriminant analysis of principal components (DAPC), which consists of determining the cluster existence in a group of genotypes where there is no a priori information about the existence of groups. The genetic diversity in the accessions was evidenced by the expected heterozygosity value (HS) (0.0279) and the population structure was evidenced by the formation of three clusters. The association mapping was performed using the GAPIT package, considering six characters: number of days for flowering (NDF), plant height (EP), panicle length (CP), plot weight (PP), mass of thousand grains (MMG) and CYCLE, as well as 24.266 silico DArTs markers and 1.965 SNPs markers. We detected a total of 113 significant associations genotype-phenotype (P <0.001) when used silico DArTs markers in all six analyzed characteristics and a total of 21 significant associations genotype-phenotype (P<0.001) when used SNPs markers for only four of the six analyzed characteristics: EP, CYCLE, MMG and PP. Considering the 113 silico DArTs significantly associated in the analysis, 90 were located in intergenic regions and 23 were localized within genes. While of the 21 significant SNPs, 11 were located in intergenic regions and 10 were located within genes. The information generated in this study was useful for testing associations throughout the rice genome. The mixed linear model (MLM) used in association mapping is believed to have been able to efficiently control false positives in the mapping using the SNPs markers. The information generated in this study serves as a basis for further evaluation using the set of significant markers as a starting point for determining the most important genes for rice yield.
254

Caracterização molecular de Trypanosoma cruzi em pacientes com doença de Chagas sem e com imunodepressão (infecção por HIV e transplante de órgãos) / Molecular characterization of Trypanosoma cruzi in patients with Chagas\' disease with and without immunesuppression (HIV infection and organ transplantation)

Silva, Sheila Cristina Vicente da 09 September 2015 (has links)
A doença de Chagas é caracterizada por um amplo espectro de manifestações clínicas, que vão desde a ausência de sintomas à doença grave com comprometimento cardíaco e/ou digestivo. A influência do parasito, Trypanosoma cruzi (T. cruzi), agente etiológico da doença, nessas apresentações clínicas têm sido largamente estudada, não se tendo demonstrado o papel da diversidade genética de populações de T. cruzi na determinação das diferentes formas clínicas em humanos. Este trabalho teve como objetivos: a) geral: analisar as características moleculares de T. cruzi em pacientes com doença de Chagas com e sem imunodepressão (infecção por HIV e transplante de órgãos com e sem reativação); b) específicos: 1. Analisar comparativamente isolados do parasito quanto à distribuição em DTU; 2. Relacionar os resultados obtidos pela análise molecular do gene ND7 com a forma clínica e origem; 3. Avaliar por LSSP-PCR a variabilidade da sequência do kDNA de T. cruzi diretamente de amostras biológicas assim como em isolados de T. cruzi obtidos pelos exames de hemocultura/xenodiagnóstico; 4. Comparar os padrões polimórficos obtidos por LSSP-PCR em amostras repetidas de um mesmo paciente no mesmo sítio ou distintos sítios biológicos. Foram incluídos, após aprovação do protocolo na CAPPesq e mediante assinatura de TCLE, 106 pacientes com doença de Chagas crônica ou com imunossupressão, provenientes dos ambulatórios e enfermarias do HCFMUSP, além de 75 indivíduos controle, com provas sorológicas e moleculares negativas. Foram analisadas 187 amostras isoladas de hemocultura/xenodiagnóstico e 236 diretamente de amostras sanguíneas de pacientes. Os seguintes grupos foram constituídos: Agudo-AG, Crônico-CR, Crônico Imunodeprimido-CRI (doenças autoimunes/neoplasias), Coinfecção-CO (infecção por HIV/T.cruzi), Coinfecção-CO/RE (infecção por HIV/T.cruzi e reativação da doença de Chagas), Transplantado-TX, Transplantado-TX/RE (Transplantado com reativação da doença de Chagas). Foram identificados DTU TcI, TcV, TcVI e em maior número TcII, por ensaios de tipagem molecular do parasito, com distribuição estatisticamente significantemente de acordo com a naturalidade dos pacientes (P=0,013). Quanto ao gene ND7, observou-se que a banda de ~900 bp ocorreu em 83,0% das amostras das regiões norte, nordeste, centro-oeste e Bolívia e a de ~400pb em 54% das amostras nas regiões sul e sudeste brasileiras sendo esta diferença estatisticamente significante (P < 0,001). A comparação dos perfis observados por LSSP-PCR a partir de amostras extraídas diretamente do sangue e de isolados obtidos de hemocultura/xenodiagnóstico mostrou maior variabilidade em amostras sanguíneas, confirmada pelo dendrograma. Adicionalmente, o estudo de amostras repetidas do mesmo paciente permitiu confirmar a maior variabilidade nas amostras diretamente extraídas do sangue, com mudança dos padrões durante e após o tratamento com reaparecimento de perfis antigos não presentes no período prétratamento imediato, além de presença de perfis diferentes em distintos sítios biológicos do mesmo paciente. O encontro de DTU diferentes de TcII nos grupos CR/CRI e AG enfatiza a necessidade de atentar para a diferença em limiares de reatividade segundo DTU na análise da parasitemia por PCRq (quantitativa), conforme registrado na literatura. Os dados observados por LSSP-PCR acrescentam informações adicionais não revelados por tipagem molecular, representando novos desafios para o entendimento da relação hospedeiro-parasito em pacientes com doença de Chagas sem e com imunossupressão, ao lado de fatores como nível de parasitemia e pressão seletiva de medicamentos antiparasitários e imunossupressores / Chagas\' disease is characterized by a broad spectrum of clinical manifestations, ranging from asymptomatic cases to severe cardiovascular and/or gastrointestinal involvement. The clinical presentations are thought to be determined primarily by genetic diversity of populations of Trypanosoma cruzi (T. cruzi), but no correlation was clearly demonstrated yet. This study aimed to: a) general: to analyze the molecular characteristics of T. cruzi in patients with Chagas\' disease with and without immunosuppression (HIV infection and organ transplantation with or without reactivation); b) specifics: 1.To analyze comparatively isolates from the parasite as for the distribution in DTU; 2. To describe the results obtained by molecular analysis of gene ND7 in relationship with the clinical form and origin; 3. To assess by LSSP-PCR the variability of the sequence of the T. cruzi kDNA directly from biological samples, as well as in T. cruzi isolates obtained by examination of blood culture/xenodiagnosis; 4. To compare the polymorphic patterns obtained by LSSP-PCR in repeated samples of the same patient on the same site or different biological sites. After approval of the protocol in CAPPesq and by signing an informed consent, 106 patients with chronic Chagas disease or immunosuppression, from the HCFMUSP\'s clinics and wards, and 75 control subjects with negative serological and molecular tests were included. They were analyzed 187 isolated samples from blood culture/xenodiagnosis and 236 directly from blood samples of patients. The following groups were formed: Acute-AC, Chronic-CR, Chronic immunocompromised-CRI (autoimmune diseases/ neoplasms), Coinfection-CO (HIV/T. cruzi infection), Coinfection-CO/RE (HIV/T. cruzi and reactivation of Chagas disease), Transplantation-TX, Transplantation-TX/RE (Transplantation/ with reactivation of Chagas\' disease). DTU TcI, TcV, TcVI and higher TcII number were identified for molecular typing assays of the parasite and the distribution of DTU was statistically significant according to patient´s naturality (P=0.013). As for ND7 gene, was observed that the band of ~ 900 bp was prevalent in 83% of the samples in the North, Northeast, Midwest regions and Bolivia and the band of ~400bp occurred in 54% of the samples of Brazilian\' South and Southeast regions, this distribution was statistically significant (P < 0.001). The comparison between the profiles observed by LSSP-PCR from samples taken directly from blood and isolates obtained from blood culture/xenodiagnosis showed greater variability in blood samples, confirmed by dendrogram. Additionally, the study of repeated samples from the same patient allowed to confirm the greater variability in blood samples taken directly, with changing patterns during and after the treatment with reappearance of old profiles not present in the immediate pre-treatment period, and the presence of different profiles at different biological sites in the same patient. The presence of other DTUs than TcII in chronic and chronic immunosuppressed patients and AC groups emphasizes the need to pay attention to the different reactivity thresholds for the various DTU in the analysis of parasitaemia by PCRq (quantitative), according to the data registered in the literature. The results observed by LSSP-PCR add further information not revealed by molecular typing, representing new challenges for the understanding of the host-parasite relationship in patients with Chagas\' disease with and without immunosuppression, alongside factors such as level of parasitaemia and selective pressure of antiparasitic drugs and immunosuppressive
255

Establishing the Value of ALS-Inhibiting Herbicides in Fields with Confirmed Weed Resistance to ALS-Inhibiting Herbicides

Jodi E Boe (6632369) 11 June 2019 (has links)
<p>Acetolactate synthase (ALS) inhibitors are a widely used class of selective herbicides used to control grass and broadleaf weeds. The repeated use of ALS-inhibiting herbicides has selected for biotypes of weeds resistant to ALS inhibitors, especially in the weeds most problematic to growers in the Midwest. While ALS inhibitor use seems futile, new mechanisms of herbicide action are not predicted to be commercialized in the near future to solve this problem. This leads to the main objective of this research, determining what value ALS inhibitors provide in controlling populations of weeds with resistance to ALS inhibitors. </p> <p>Field experiments with soil-applied (PRE) applications of ALS inhibitors on horseweed (<i>Erigeron canadensis</i>) and tall waterhemp (<i>Amaranthus tuberculatus </i>var. <i>rudis</i>) exhibited higher efficacy than would be expected given the frequency of the ALS resistance trait in the population. Whereas control of these species with POST-applied applications was similar or less than the proportion of the population characterized as susceptible using molecular techniques. Soil-applied applications, therefore, resulted in relatively greater control than POST applications in populations with known ALS-inhibitor-resistance mechanisms.</p> <p>Greenhouse experiments showed that overall resistance ratios were higher for PRE applications of ALS inhibitors in horseweed, tall waterhemp, and Palmer amaranth (<i>Amaranthus palmeri</i>). However, GR<sub>50</sub> values decreased for both susceptible and resistant biotypes for the PRE applications compared to POST, suggesting the biologically effective dose of these herbicides is lower in soil residual applications. This research found that PRE applications of ALS inhibitors resulted in some level of control on horseweed and tall waterhemp classified as resistant to ALS inhibitors due to the higher efficacy of PRE herbicide applications.</p> <p>Genetic analysis assessing the amino acid substitutions that confer resistance to ALS inhibitors in tall waterhemp confirmed a difference in selection pressure between PRE and POST applications and between ALS active ingredients in tall waterhemp. Applications of chlorimuron PRE at 11 g ai ha<sup>-1 </sup>selected for 35% homozygous W574L genotypes and at 44 g ha<sup>-1</sup> selected for 70% homozygous W574L genotypes. An increase of homozygous W574L individuals along with a decrease in heterozygous individuals from 65 (11 g ha<sup>-1</sup>) to 29% (44 g ha<sup>-1</sup>) suggests that W574L is semi-dominant in tall waterhemp and that high labeled rates of chlorimuron applied PRE can partially overcome the heterozygous W574L-resistance mechanism. In horseweed, no difference in selection pressure was observed between application timing or between chlorimuron or cloransulam. A new mutation conferring ALS-inhibitor resistance in horseweed was discovered, a Pro197Leu amino acid substitution, with resistance ratios of 21X to chlorimuron and 8.6X to cloransulam. These resistance ratios are slightly less than those reported for the Pro197Ala and Pro197Ser amino acid substitutions in conferring ALS-inhibitor resistance in horseweed. </p> <p>Finally, a survey of 42 populations of tall waterhemp in Indiana counties with confirmed ALS-inhibitor resistant populations of tall waterhemp found that all populations contained at least 16% individuals with the W574L amino acid substitution, 35 populations contained at least 1% individuals with the S653N substitution, and 9 populations contained at least 1% individuals with the S653T substitution. Taking into consideration the three mutations tested, 8 of the 42 populations tested contained <50% ALS-inhibitor resistant individuals within the population. Using the same tall waterhemp populations as collected in the survey, Next-Generation Sequencing was used to determine if other amino acid substitutions conferring resistance to ALS inhibitors existed. Results from WideSeq revealed that 10 other amino acid substitutions in the ALS protein may be conferring resistance in tall waterhemp in Indiana: A122T, A122N, A122S, P197T, P197L, P197H, D376E, and G654F. Further research from this survey also suggests that metabolic resistance to ALS inhibitors is likely a contributor to resistance in tall waterhemp in Indiana.</p> <p>This research suggests that ALS-inhibiting herbicides, more specifically chlorimuron, would provide the greatest contribution to management of tall waterhemp. Chlorimuron would perform best when used in soil residual applications and in populations of tall waterhemp containing either individuals susceptible to chlorimuron or individuals heterozygous for ALS inhibitor resistance conferred by the W574L mutation. This research also demonstrates the specificity of the amino acid substitutions in the ALS protein and by weed species to realize the benefit of these herbicides for management of weeds resistant to ALS inhibitors. Molecular characterization of target site resistance to ALS inhibitors has traditionally been considered relatively simple. However, we found 11 new amino acid substitutions that confer resistance to ALS inhibitors in horseweed and tall waterhemp. The complexity of ALS inhibitor resistance calls for the use of methods such as NGS to detect all potential resistance mutations in a timely manner and for the use of tests detecting metabolic resistance. Overall, this research demonstrates that ALS inhibitors still provide some utility for management of weed populations classified as resistant to ALS inhibitors and that the resistance mechanisms in horseweed and tall waterhemp are more numerous than previously reported. </p>
256

Reinfecção experimental de camundongos Balb/c por cepas geneticamente distintas de Toxoplasma gondii / Experimental reinfection of Balb/c mice by genetically distinct strains of Toxoplasma gondii

Santos, Talita Caroline Coelho dos 08 January 2018 (has links)
A infecção por Toxoplasma gondii, em hospedeiros imunocompetentes, resulta no desenvolvimento de anticorpos específicos e resposta imune celular que, frequentemente, induzem imunidade protetora e duradoura, prevenindo reinfecção. Entretanto, casos de toxoplasmose congênita em mulheres imunocompetentes em fase crônica de infecção indicam a possibilidade de reinfecção em humanos. Em modelos experimentais, reinfecção por T.gondii já foi descrita em casos de infecção por cepa de genótipo distinto ao da infecção primária e por cepas recombinantes, porém os estudos envolvendo genótipos clonais, em modelo murino, restringem-se à utilização de cepas do genótipo II na infecção primária, com desafio subsequente por cepas do mesmo genótipo, ou dos genótipos I e III, com ausência de informações sobre as cepas do tipo III, que correspondem ao genótipo de maior frequência e distribuição mundial. Procuramos explorar vários modelos de infecção sequencial com cepas clonais dos tipos I, II e III, buscando dados mais consistentes para compreensão dos seguintes questionamentos: (i) A infecção primária por um genótipo de T.gondii é capaz de proteger o hospedeiro da reinfecção por genótipo distinto? (ii) A imunidade induzida pela infecção primária pode prevenir a progressão da infecção causada pela cepa secundária, impedindo doença aguda e mortalidade dos animais? (iii) A imunidade da infecção primária previne a colonização do cérebro por cistos teciduais da cepa secundária? Nossos dados mostram que a imunidade induzida pela infecção primária por cepas clonais de T.gondii não protege o hospedeiro da reinfecção por cepa de genótipo distinto, já que foram detectados anticorpos contra as cepas das infecções primária e secundária em todos os modelos propostos. Somente a imunidade induzida pela infecção primária por cepa do tipo III foi capaz de prevenir a progressão da infecção secundária causada pelas cepas do tipo I e do tipo II, impedindo a mortalidade e colonização do cérebro dos animais por cistos teciduais da cepa secundária. Esses achados são extremamente importantes para auxiliar estudos vacinais e terapêuticos da toxoplasmose. / Toxoplasma gondii infection in immunocompetent hosts results in the development of specific antibodies and cellular immune responses that often induce protective and lifelong immunity, preventing reinfection. However, cases of congenital toxoplasmosis in immunocompetent women at a chronic phase of infection indicate the possibility of reinfection in humans. In experimental models, reinfection by T.gondii has been described in cases of infection by genotype distinct from that of primary infection and by recombinant strains, but studies involving clonal genotypes in the murine model are restricted to the use of type II genotype in primary infection, with subsequent challenge by strains of the same genotype, or genotypes I and III, without information about type III strains, which correspond to the genotype with the highest frequency and worldwide distribution. We explore several models of sequential infection with clonal strains of types I, II and III, looking for more consistent data to understand the following questions: (i) Primary infection by a T.gondii genotype is able to protect the host from reinfection by different genotype? (ii) Does the immunity induced by the primary infection prevent the progression of infection caused by the secondary strain, preventing acute disease and animal mortality? (iii) Does the immunity of primary infection prevent colonization of the brain by tissue cysts of the secondary strain? Our data show that the immunity induced by primary infection by T.gondii clonal strains does not protect the host from reinfection by a distinct genotype strain, since antibodies against the strains of primary and secondary infections were detected in all proposed models. Only the immunity induced by the primary infection by type III strain was able to prevent the progression of the secondary infection caused by type I and type II strains, preventing the mortality and colonization of the brains of the animals by tissue cysts of the secondary strain. These findings are extremely important to support vaccine and therapeutic studies of toxoplasmosis.
257

Toxoplasma gondii: prevalência de infecção, diagnóstico laboratorial e genótipos. / Toxoplasma gondii: prevalence of infection, laboratory diagnosis and genotype.

Mattos, Cinara de Cássia Brandão de 13 April 2012 (has links)
Made available in DSpace on 2016-01-26T12:51:36Z (GMT). No. of bitstreams: 1 cinaradecassiabrandaodemattos_tese.pdf: 2369764 bytes, checksum: d694ab0e38db337b769ea1ace729b6e3 (MD5) Previous issue date: 2012-04-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / T. gondii is an obligate intracellular parasite and cosmopolitan, whose infection congenital or acquired, results in different forms of toxoplasmosis. The clinical manifestations of this disease are nonspecific and variable. Its diagnosis essentially laboratory is aimed at pregnant women, neonates, patients with immunodeficiencies, patients with eye injury and even normal individuals. Serological methods are often used in the characterization of IgM and IgG anti-T.gondii, but those of nature of molecular favoring genetic characterization of the strains isolated from biological samples. Objectives: The overall objective of this thesis was to investigate the infection by T.gondii in the northwestern region of São Paulo state. Its specific objectives were: 1. to characterize infection in pregnant women, newborns and people with eye diseases 2. to evaluate the applicability of the method of PCR inperipheral blood sample in patients with eye diseases 3. to identify the strains from peripheral blood samples. Casuisitc and Methods: epidemiological data and samples of peripheral blood from patients treated in Outpatient Clinic of High Risk Pregnancy and Retinopathy were collected and analyzed for infection by T. gondii using serological methods (ELISA) and molecular (cnPCR and qPCR). Results: among 574 women with mean age equal to 27.2 ± 6.5, 62% (345/556) showed positive for IgG and 3.4% (n = 19/556) for IgM. In 87 mother-newborn pairs, 64.4% (n = 58) were reactive for anti-T. gondii and 2.3% (n = 2), IgM, 92.9% (52/56) had IgG avidity greater than or equal to 30%. Among 184 patients with different eye diseases, 26% (n = 49) had ocular toxoplasmosis, all reagents for IgG. The PCR (qPCR and cnPCR) applied to the analysis of peripheral blood showed sensitivity and specificity equal to 40.8% and 100%, respectively. Five patients with ocular toxoplasmosis were shown to be infected by the strain toxoDB # 65. Conclusion: The results show that the prevalence of infection with T. gondii in pregnant women, neonates and patients with eye diseases is high in the northwertern region of São Paulo state, and to estimate the rates of congenital infection in the region. In addition to describing the first time the ocular toxoplasmosis in the region, this study reinforces the importance of cnPCR and qPCR methods for the characterization of infection and laboratory strains toxoDB # 65 from peripheral blood samples of patients with chronic infection. / T. gondii é um parasito intracelular obrigatório e cosmopolita, cuja infecção de natureza congênita ou adquirida, resulta nas diferentes formas de toxoplasmose. A manifestação clínica desta doença é inespecífica e variável. Seu diagnóstico, essencialmente laboratorial, é direcionado a gestantes, neonatos, portadores de imunodeficiências, portadores de lesão ocular e mesmo indivíduos normais. Métodos sorológicos são frequentemente utilizados na caracterização de anticorpos IgM e IgG anti-T. gondii, porém aqueles de natureza molecular favorecem a caracterização gênica das cepas em isolados de amostras biológicas. Objetivos: O objetivo geral desta tese foi investigar a infecção por T. gondii na região Noroeste Paulista. Seus objetivos específicos foram: 1. caracterizar a infecção em gestantes, neonatos e indivíduos com doenças oculares; 2. avaliar a aplicabilidade do método de PCR em amostra de sangue periférico em pacientes com doenças oculares; 3. identificar as cepas a partir de amostras de sangue periférico. Casuísitca e Métodos: dados epidemiológicos e amostras de sangue periférico de pacientes atendidos em Ambulatório de Gestação de Alto Risco e Retinopatia foram coletadas e analisadas quanto à infecção por T. gondii por métodos sorológicos (ELISA) e moleculares (cnPCR e qPCR). Resultados: entre 574 gestantes com média de idade igual a 27,2±6,5, 62% (345/556) mostraram-se reagentes para IgG e 3,4% (n=19/556), para IgM. Em 87 pares mãe-bebê, 64,4% (n=58) foram reagentes para anti-T. gondii e 2,3% (n=2), para IgM; 92,9% (52/56) apresentaram IgG com avidez maior ou igual a 30%. Dentre 184 pacientes com diferentes doenças oculares, 26% (n=49) apresentaram toxoplasmose ocular, todos reagentes para IgG. O método PCR (cnPCR e qPCR) aplicado à análise do sangue periférico apresentou sensibilidade e especificidade iguais a 40,8% e 100%, respectivamente. Cinco pacientes com toxoplasmose ocular mostraram-se infectados pela cepa toxoDB#65. Conclusão: Os resultados demonstram que a prevalência de infecção por T. gondii em gestantes, neonatos e pacientes com doenças oculares é elevada na região Noroeste paulista, e permitem estimar os índices de infecção congênita na região. Além de descrever pela primeira vez a toxoplasmose ocular na região, este estudo reforça a importância dos métodos cnPCR e qPCR na caracterização laboratorial da infecção e da cepas toxoDB #65 a partir de amostras de sangue periférico de pacientes com infecção crônica.
258

Testing new genetic and genomic approaches for trait mapping and prediction in wheat (Triticum aestivum) and rice (Oryza spp)

Ladejobi, Olufunmilayo Olubukola January 2018 (has links)
Advances in molecular marker technologies have led to the development of high throughput genotyping techniques such as Genotyping by Sequencing (GBS), driving the application of genomics in crop research and breeding. They have also supported the use of novel mapping approaches, including Multi-parent Advanced Generation Inter-Cross (MAGIC) populations which have increased precision in identifying markers to inform plant breeding practices. In the first part of this thesis, a high density physical map derived from GBS was used to identify QTLs controlling key agronomic traits of wheat in a genome-wide association study (GWAS) and to demonstrate the practicability of genomic selection for predicting the trait values. The results from GBS were compared to a previous study conducted on the same association mapping panel using a less dense physical map derived from diversity arrays technology (DArT) markers. GBS detected more QTLs than DArT markers although some of the QTLs were detected by DArT markers alone. Prediction accuracies from the two marker platforms were mostly similar and largely dependent on trait genetic architecture. The second part of this thesis focused on MAGIC populations, which incorporate diversity and novel allelic combinations from several generations of recombination. Pedigrees representing a wild rice MAGIC population were used to model MAGIC populations by simulation to assess the level of recombination and creation of novel haplotypes. The wild rice species are an important reservoir of beneficial genes that have been variously introgressed into rice varieties using bi-parental population approaches. The level of recombination was found to be highly dependent on the number of crosses made and on the resulting population size. Creation of MAGIC populations require adequate planning in order to make sufficient number of crosses that capture optimal haplotype diversity. The third part of the thesis considers models that have been proposed for genomic prediction. The ridge regression best linear unbiased prediction (RR-BLUP) is based on the assumption that all genotyped molecular markers make equal contributions to the variations of a phenotype. Information from underlying candidate molecular markers are however of greater significance and can be used to improve the accuracy of prediction. Here, an existing Differentially Penalized Regression (DiPR) model which uses modifications to a standard RR-BLUP package and allows two or more marker sets from different platforms to be independently weighted was used. The DiPR model performed better than single or combined marker sets for predicting most of the traits both in a MAGIC population and an association mapping panel. Overall the work presented in this thesis shows that while these techniques have great promise, they should be carefully evaluated before introduction into breeding programmes.
259

Diversité des réponses écophysiologiques et moléculaires pour un complexe de frênes européens (Fraxinus angustifolia Vahl et Fraxinus excelsior L. et leurs hybrides) face à la contrainte hydrique / Diversity of ecophysiological and molecular responses for a complex of European ash (Fraxinus angustifolia Vahl and Fraxinus excelsior L.) and their relative hybrids facing water constraint.

Joseph, Romain 09 December 2013 (has links)
Les derniers scénarios du changement climatique, prévoient une élévation de température (Europe, +2 à +4°C en moyenne en 2099, IPCC, 2007) associée à des épisodes extrêmes, sécheresses sévères par exemple. Connaître les potentialités d'adaptation des espèces forestières s'avère crucial afin de comprendre leurs réponses et le devenir des écosystèmes forestiers, dans un futur proche. Dans ce cadre, nous nous sommes intéressés à un complexe d'espèces du genre Fraxinus, (frêne, Oléacées). En France F. excelsior L., et F. angustifolia, Vahl, sont des espèces autochtones présentant une plasticité phénotypique et écologique remarquable. L'hybridation, suspectée depuis longtemps a été prouvée en conditions contrôlées et naturelles. Les principales zones documentées sont la vallée de la Saône et de la Loire. Cette hybridation entre les deux espèces de frênes européens, pourrait favoriser l'apparition d'individus (génotypes) plus aptes que les espèces parentales à faire face à un environnement changeant. Notre objectif est de caractériser les potentialités d'adaptations de différentes populations de frêne (espèces parentales et de statut hybride) sous une contrainte abiotique (contrainte hydrique). Pour répondre à cet objectif, nous avons testé les réponses à la fois écophysiologiques et génétique de jeunes plants à une contrainte légère (-0,9 MPa). Une seconde expérimentation, centré sur l'écophysiologie a eu pour objet de mesurer la perte de conductivité hydraulique des frênes, sous une forte contrainte (-4 MPa). Le principal résultat de ces travaux est le comportement souvent intermédiaire et très variable des populations de frênes hybrides testés dans ces 2 expérimentations (A, gs, WUEi, PLC), que ce soit en conditions avec ou sans contrainte hydrique. Ce comportement intermédiaire est en lien avec le degré d'introgression respectif des hybrides de frênes (plus proche de F.excelsior ou de F.angustifolia). Ces arbres hybrides pourraient servir de ressources et d'assurance contre des évènements de dépérissement catastrophiques pour les forestiers pour un environnement climatique futur. / The latest climate change scenarios predict a rise in mean temperature in Europe of 2 to 4°C for 2099 (IPCC, 2007), associated with extreme climatic events such as severe droughts. Knowing adaptation capabilities of tree species is crucial for understanding their responses and forest ecosystem fate in the near future. Our study object is a species complex inside the Fraxinus genus (ash, Oleaceae). In France, F. excelsior and F. angustifolia are autochthonous, form natural hybrid populations and show remarkable phenotypic and ecological plasticity. This could promote the emergence of new individuals (genotypes) more able to deal with fluctuating environments. Our objective is to characterise the capability of adaptation of different Fraxinus populations, representing the three statuses (F.excelsior, F.angustifolia and hybrids) under abiotic constraints (water constraint). To solve this issue, we examine in a low water constraint experiment (-0.9 MPa) ecophysiological and genetic response, using saplings. A second and more severe water constraint experiment (-4 MPa) was used to investigate ash response to the loss of hydraulic conductivity. The most noticeable result was an intermediate and highly variable behaviour of hybrid ash populations in the two experiments (A, gs, WUEi, PLC) linked with they respective introgression degree (closer to F.excelsior or F.angustifolia). This hybrid trees could be used for foresters as a resource and insurance against catastrophic forest stand decline, for a future climate.
260

Acompanhamento clínico-laboratorial da utilização de Enfuvirtida em pacientes HIV soropositivos multiexperimentados atendidos nos ambulatórios do Hospital Universitário Pedro Ernesto / Clinical and laboratory monitoring of the use of Enfuvirtide in multi-experienced HIV-seropositive patients treated in the outpatient clinics of Hospital Universitário Pedro Ernesto

Jadir Rodrigues Fagundes Neto 15 June 2012 (has links)
A Enfuvirtida(ENF), único inibidor de fusão disponível, representa uma opção interessante aos pacientes com infecção pelo HIV quando utilizada em combinação com outros antirretrovirais, principalmente no tratamento de multiexperimentados com falha virológica e poucas opções terapêuticas. Sua eficácia já comprovada em ensaios clínicos esbarra nas barreiras impostas por sua administração parenteral. Impulsionado por estes dados, avaliamos durante 48 semanas a resposta virológica, a evolução de células T CD4 a possível resistência primária a ENF e o impacto para a adesão do uso subcutâneo da droga em dez pacientes que fazem acompanhamento ambulatorial no Hospital Universitário Pedro Ernesto e que tinham história de mais de dez anos de infecção pelo HIV e uso de ENF no seu esquema terapêutico sugerido por teste de resistência. Todos os pacientes alcançaram ao final do seguimento sucesso terapêutico, mantendo carga viral não detectada, e um incremento médio significativo de linfócitos T CD4. Em relação a uma possível resistência primária, em nenhum dos testes, genotipagem da glicoproteína 41, foi visualizado mutações naturais que pudessem diminuir a ação da ENF. Sobre o manejo do medicamento, preparo e aplicação, observamos que é imprescindível um apoio multidisciplinar para que não haja descontinuação na sua utilização / Enfuvirtide (ENF) is the only fusion inhibitor available. It is an interesting option for patients with HIV infection when used in combination with other antiretroviral drugs, especially in the treatment of multi-experienced patients with virological failure and few therapeutic options. Its effectiveness confirmed in clinical trials finds the barriers in its parenteral administration. Using these data, we evaluated, for 48 weeks, the virological response, evolution of CD4 T cells, the possible primary resistance to ENF and the impact to the subcutaneous use of the drug in ten patients undergoing outpatient monitoring at Hospital Universitário Pedro Ernesto with a history of more than ten years of HIV infection and use of ENF in their therapy, as suggested by resistance testing. All patients have successfully completed the therapy by the end of follow-up with an undetected viral load and a significant average increase of CD4 T lymphocytes. As for a possible primary resistance, neither the genotyping nor the glycoprotein 41 revealed natural mutations that could diminish the effect of ENF. Concerning the management, preparation and application of the drug, we found that a multidisciplinary support is essential to avoid that the drug be discontinued

Page generated in 0.0822 seconds