Thesis (M.S.)--University of North Carolina at Wilmington, 2005. / Includes bibliographical references (leaves: [44]-53)

Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2006. / Dr. Suzanne B. Shuker, Committee Chair ; Dr. Thomas M. Orlando, Committee Co-Chair ; Dr. Donald F. Doyle, Committee Member ; Dr. C. David Sherrill, Committee Member ; Dr. Andreas S. Bommarius, Committee Member ; Dr. S. Michele Owen, Committee Member ; Dr. Vicky L. H. Bevilacqua, Committee Member.

Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

No description available.

Made available in DSpace on 2014-08-13T14:50:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-24Bitstream added on 2014-08-13T17:59:57Z : No. of bitstreams: 1 000768576_20150224.pdf: 717853 bytes, checksum: 7408062cb04624121242b566d21504b8 (MD5) Bitstreams deleted on 2015-02-27T13:20:27Z: 000768576_20150224.pdf,Bitstream added on 2015-02-27T13:21:08Z : No. of bitstreams: 1 000768576.pdf: 1163804 bytes, checksum: c3cfaf6eb851846fa541ad311558450c (MD5) / A coinfecção HIV/VHC tornou-se um importante problema de saúde pública devido à possibilidade desses vírus agirem sinergicamente, acelerando a progressão da doença hepática relacionada ao VHC e podendo favorecer a proliferação do HIV. Apesar de estabelecido que a alta variabilidade genética do HIV gera mutações, conferindo ao vírus a capacidade de responder rapidamente as alterações da pressão seletiva exercida pelo sistema imunológico ou pela terapia antirretroviral (TARV), não é conhecido se a presença do VHC pode favorecer a emergência de variantes do HIV resistentes. Assim, este estudo teve como objetivo avaliar o perfil de mutações de resistência a inibidores de transcriptase reversa: Inibidores de Transcriptase Reversa análogo nucleosídeo ou nucleotídeo (ITRNs), Inibidores de Transcriptase Reversa não análogo nucleosídeo (ITRNNs); e inibidores de protease (IPs) em variantes de HIV circulantes em indivíduos coinfectados pelo VHC. Foram incluídos 19 pacientes coinfectados pelos vírus HIV/VHC, maiores de 18 anos, com carga viral plasmática do HIV de pelo menos 1.000 cópias de RNA/mL, atendidos no Ambulatório de Gastroenterologia da Faculdade de Medicina de Botucatu e, no Hospital dia “Domingos Alves Meira”. A genotipagem e o sequenciamento foram realizados no Laboratório de Biologia Molecular do Hemocentro de Botucatu, Faculdade de Medicina, UNESP, utilizando o Trugene HIV-1 Genotyping Kit (Siemens HealthcareDiagnóstics, Inc. Tarrytown, NY, USA). Foram observados dois subtipos do HIV-1, B e F, sendo o subtipo B o mais freqüente, 94,74%. Para o VHC foram observados os genótipos 1 (94,74%) e 3 (5,26%). Todos os pacientes apresentaram mutações de resistência as classes avaliadas, tendo maior freqüência mutações associadas aos ITRNs como M184V em 57,89%. As mutações associadas aos ITRNNs mais freqüentes foram a K103N e G190A, presentes em 21,05% das amostras. As mutações principais ... / HIV/HCV coinfection has become an important public health problem due to the possibility of these viruses act synergistically, which can accelerate the progression of liver disease related to HCV and may favor the spread of HIV. It is established that the high genetic variability of HIV generates mutations, giving the virus the ability to respond quickly to changes in selective pressure exerted by the immune system or by antiretroviral therapy (ART). It is not known whether the presence of HCV can promote the emergence of resistant variants of HIV. Thus, this study aimed to evaluate the profile of resistance mutations to classes of reverse transcriptase inhibitors: nucleoside and nucleotide analogue Reverse Transcriptase Inhibitors (NRTIs), non-nucleoside analogue Reverse Transcriptase Inhibitors (NNRTIs) and protease inhibitors (PIs), in circulating HIV variants in HCV coinfected individuals. In this study were included 19 HIV/HCV coinfected patients, over 18, with plasma HIV viral load of at least 1,000 RNA copies/mL. These patients were treated at the Ambulatory of Gastroenterology of the Faculty of Medicine of Botucatu and at the Day-Hospital “Domingos Alves Meira”. Genotyping and sequencing were performed at the Laboratory of Molecular Biology of the Blood Center of Botucatu, Faculty of Medicine, UNESP, using the Trugene HIV-1 Genotyping Kit (Siemens HealthcareDiagnóstics, Inc. Tarrytown, NY, USA). Two subtypes of HIV-1, B and F, were observed, but the subtype B was observed more often, 94.74%. It was observed HCV genotypes 1 (94.74%) and 3 (5.26%). All patients presented resistance mutations to the evaluated classes, and the mutations associated to NRTIs as M184V were observed more often (57.89%). The most common mutations associated to NNRTIs were K103N and G190A, present in 21.05% of the samples. The main mutations associated to IPs more frequent were M46I, I54V and V82A, with 15.78% ...

Orientadores: Jose Paulo Cabral de Vasconcellos, Vital Paulino Costa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-04T19:48:33Z (GMT). No. of bitstreams: 1 Cella_WenerPassarinho_M.pdf: 8448689 bytes, checksum: a8a8a7a3ca810183c1f5f3f2964e8c29 (MD5) Previous issue date: 2005 / Resumo: A Síndrome de Axenfeld-Rieger é uma entidade clínica rara, de transmissão autossômica dominante e grande variabilidade clínica, podendo chegar à penetrância incompleta. Manifesta-se clinicamente por malformações do segmento anterior do olho acompanhada ou não de malformações extra-oculares, das quais as mais comuns são alterações dos ossos craniofaciais e dos dentes e falência de involução da pele peri-umbilical. O principal fator de morbidade da síndrome é a associação com glaucoma de desenvolvimento, presente em aproximadamente 50% dos indivíduos afetados. Dois genes, PITX2, localizado no cromossomo 4q25, e FOXCl, no cromossomo 6 p25, estão associados à Síndrome de Axenfeld-Rieger. Recentemente, identificou-se o gene GJAl associado à Síndrome de Displasia Oculodentodigital, a qual compartilha aspectos clínicos com a Síndrome de Axenfeld-Rieger tais como malformações do segmento anterior ocular, glaucoma e alterações ósseas e dentárias, tornando-se, assim também, mais um gene candidato para a Síndrome de Axenfeld-Rieger. O objetivo deste estudo foi avaliar a ffeqüência e os tipos de mutações nos genes PITX2, FOXCl e GJAl em pacientes portadores da Síndrome de Axenfeld-Rieger associada a glaucoma, além de correlacionar possíveis alterações moleculares com aspectos clínicos dos pacientes. Para tanto, foram examinados oito indivíduos (casos-índice) acometidos pela síndrome associada a glaucoma, assim como seus familiares. Após avaliação oftalmológica e sistêmica, foram coletados 5ml de sangue periférico para extração de DNA genômico, o qual foi amplificado por reação em cadeia de polimerase utilizando-se pares de iniciadores específicos para as regiões codificadoras e limites íntronJexon dos genes PITX2, FOXCl e GJAl, procedendo-se com o seqüenciamento automático para o rastreamento de mutações. Não foram encontradas mutações no - gene PITX2. No gene FOXCl foram encontradas uma inserção (1359-1360insGGC), uma deleção (718-719deICT) e uma mutação de ponto do tipo sem sentido (TrpI52STOP) entre as famílias estudadas. O paciente portador da deleção no gene FOXCl era um caso isolado e apresentava apenas alterações oculares da síndrome. As outras duas mutações ocorreram em pacientes com manifestações oculares e sistêmicas da doença, estando a inserção presente em um caso isolado e a mutação sem sentido em seis indivíduos da mesma família com padrão de transmissão autossômico dominante. O rastreamento de mutações no gene GJAl evidenciou uma mutação de ponto do tipo sentido trocado (Ala253Val) em três indivíduos da mesma família, sendo que um deles era clinicamente normal e dois sintomáticos que apresentavam concomitantemente a mutação Trp152STOP no gene FOXCl. Esta é a primeira descrição de uma mutação no gene GJAl em pacientes inequivocamente portadores da Síndrome de Axenfeld-Rieger. As ITeqüências de mutações observadas nos genes PITX2, FOXCl e GJAl em oito famílias brasileiras com Síndrome de Axenfeld-Rieger e glaucoma de desenvolvimento associado foram de 0%, 37,5% e 12,5%, respectivamente, sendo esta última em combinação com a mutação Trp152STOP no gene FOXCl. Apesar da amostragem reduzida, observou-se uma tendência a maior agressividade do glaucoma em pacientes portadores de mutação somente no gene FOXCl do que nos indivíduos portadores de mutação concomitante no gene FOXCl e no gene GJAl, sugerindo um possível efeito protetor da mutação Ala253Val no gene GJAl nesta família. Outros estudos são necessários, contudo, para definir a função do gene GJAl na etiopatogênese da Síndrome de Axenfeld-Rieger / Abstract: Axenfeld-Rieger Syndrome (ARS) is arare disorder, usually transmitted in an autosomal dominant pattem characterized by anterior segment dysgenesis and often associated with developmental glaucoma. In addition to the ocular changes observed in ARS, syndromic features can also occur, such as facial bone defects, teeth anomalies and peri-umbilical skin involution. Two transcription factor genes, PITX2 on chromosome 4q25 and FOXCl on chromosome 6p25, have been associated with the ARS phenotype through mutational events. Recently, the GJAl gene (connexin 43), associated with oculodentodigital dysplasia (ODDD) syndrome, which presents some similarities with ARS, was identified. The ODDD syndrome is characterized by malformations that involve the face, eyes, teeth and bones. The ocular abnormalities include microphthalmos and anterior segment dysgenesis that may lead to glaucoma as well. The main purpose of this study was to evaluate FOXCl, PITX2 and GJAl genes mutations in Brazilian patients with ARS. Eight unrelated patients atfected by ARS (all of them with glaucoma and 5 without systemic malformations) and their families were ophthalmologically evaluated and had their blood collected for DNA extraction purposes. The coding regions and íntron/exon boundaries of these genes were completely evaluated through direct sequencing. Among the 8 patients, 3 (37,5%) presented with ditferent structural alterations in the FOXCl gene. A deletion in heterozygosis oftwo bases downstream the forkhead domaÍn was observed in a patient with no systemic malformations (718-719deICT). An insertion ofthree bases, also downstream the forkhead domain, was identified in a patient with systemic malformation (1359-1360insGGC). A new nonsense mutation (Trp152STOP) was identified in the forkhead domain of the FOXCl gene in another patient with ARS and systemic alterations as well. One patient harbored the mutation Ala253Val in the GJAl gene (12,5%). No mutations were identified in the PITX2 gene among these individuaIs. Patients who carried the GJAl (Ala253Val) and FOXCl (TrpI52STOP) mutations (:&om the same family) developed less severe glaucoma compared with family members presenting FOXCl (TrpI52STOP) mutation alone. Three new structural alterations of the FOXCl gene and one new mutation in the GJAl gene were described in Brazilian patients with ARS and the :&equencyof mutations in the PITX2, FOXCl and GJAl genes in this study were 0%, 37,5% and 12,5%, respectively. Despite the small number of patients, we found a slight trend to more severe glaucoma in patients with FOXCl mutations compared to those without them, except in the two patients with FOXCl and GJAl associated mutations, suggesting an attenuation effect of GJAl gene mutation (Ala253Vai). However, other studies are necessary to define the exact role ofGJAl in ARS / Mestrado / Oftalmologia / Mestre em Ciências Médicas

Orientador: Edi Lucia Sartorato / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-13T04:28:58Z (GMT). No. of bitstreams: 1 Silva-Costa_SueliMatildeda_M.pdf: 4568147 bytes, checksum: d8aadad3b82357deab2dec0ee176e6ed (MD5) Previous issue date: 2009 / Resumo: Mutações no gene GJB2 (Cx26) são as causas mais comuns de perda auditiva não-sindrômica autossômica recessiva. Contudo, 10 a 40% dos casos com mutações no gene da Cx26 são detectadas em apenas um dos alelos, causando um problema no diagnóstico molecular. Estes achados podem ser atribuídos à existência de mutações em regiões não codificantes do gene ou mutações em outros genes cujos produtos protéicos estão envolvidos em interações com a Cx26. O principal objetivo deste trabalho foi esclarecer a causa genética da perda auditiva de 45 pacientes com surdez sensorioneural não-sindrômica monoalélicos para mutações patogênicas na região codificante do gene GJB2. Mutações incluindo deleções e duplicações nos genes GJB2, GJB3 e GJB6 foram investigadas nesses pacientes. A mutação IVS1+ lG>A no sítio de splice na região não codificante do gene GJB2, que pode contribuir para o fenótipo de surdez, foi também investigada em todos os 45 pacientes. A fim de avaliar a freqüência da mutação IVS1+1G>A em pacientes brasileiros foram analisados 142 pacientes com perda auditiva sensorioneural não-sindrômica que não apresentavam nenhuma mutação patogência na região codificante do gene GJB2. Além disso, o método de MLP A (Multiplex Ligationdependent Probe Amplification) foi utilizado neste estudo para avaliar sua eficiência em detectar deleções e duplicações em genes envolvidos na perda auditiva. Analisando todos os pacientes, dez diferentes mutações no gene GJB2 e uma deleção no gene GJB6 foram encontradas.. Esses achados explicaram a perda auditiva de aproximadamente 27% dos pacientes monoalélicos para mutações no gene GJB2. A mutação IVSl+IG>A foi encontrada em dois pacientes monoalélicos. Essa alteração não foi encontrada nos pacientes sem mutações na região codificante do gene GJB2. Essa mutação parece ser rara entre pacientes surdos brasileiros. Na região promotora do gene, em um paciente, uma deleção foi encontrada e no outro uma duplicação foi observada por meio do método de MLP A. Essas possíveis alterações na região não codificante do gene ainda não foram descritas. Outras análises moleculares e estudos funcionais são necessários para confirmar uma possível associação desses achados com a perda auditiva. A técnica de MLP A se mostrou eficiente para detectar deleções e duplicações no genoma. Portanto, demonstramos no presente estudo que essa técnica pode contribuir para explicar a surdez em pacientes monoalélicos. / Abstract: Mutations in the GJB2 gene (Cx26) are the most common cause of autosomal recessive nonsyndromic hearing loss. However, in 10 to 40% of these cases, mutations in Cx26 gene are detected in on1y one allele which causes a problem in molecular diagnostico These findings could be attributed to the existence of mutations in non-coding regions of the gene or mutations in other genes of which protein products are involved in interaction with Cx26. The aim of this study was to clarifying the genetic cause of the hearing loss of 45 patients with non-syndromic sensorioneural deafness, monoallelics for pathogenic mutations in the coding region of the GJB2 gene. Mutations including deletions and duplications in the GJB2, GJB3 and GJB6 genes were investigated in these patients. 'The IVSl+ 1G>A splice site mutation in the non-coding region of the GJB2 gene which can contribute to the deafuess phenotype was also investigated in all 45 patients. In order to evaluate the frequency of the IVSl+ 1G>A mutation were tested 142 Brazilian patients with non-syndromic sensorineural hearing loss without any pathogenic mutation ín the GJB2 coding region. Furthermore, the MLP A method (Multiplex Ligation-dependent Probe Amplification) was used to evaluate its usefulness in detecting deletions/duplications in genes involved in hearing loss. Ten different mutations in the GJB2 gene and one deletion in the GJB6 gene were found. These findings eXplained the hearing loss about 27% ofGJB2 monoallelic patients. The IVSl+ 1G>A mutation was found in two monoallelics patients. This alteration was not found in patients without mutations in the GJB2 coding region. This mutation seems to be rare in deaf Brazilian patients. One patient a deletion was found in the promoter region of GJB2 gene and in another patients a duplication was observed by the MLP A method. These possible alterations were not described in noncoding region of GJB2 gene yet. Additional molecular and functional studies are needed to assess a possible association of these findings with hearing loss. MLP A proved to be a highly accurate method to detected deletions and duplications in the genome. Therefore, we have shown in the present study that this technique can explain the deafness in monoallelics patients. / Mestrado / Genetica Animal e Evolução / Mestre em Genética e Biologia Molecular

It is generally known that media containing simple sugars (sucrose, glucose) and organic nitrogen sources (ammonium) when buffered to acidic pH stimulates aflatoxin production in Aspergillus flavus & A. parasiticus while lactose, nitrate and an alkaline pH inhibit aflatoxin biosynthesis. It has been shown that pH of the growth medium is the most important regulatory factor for aflatoxin biosynthesis since media containing stimulatory carbon and/or nitrogen sources (sucrose and ammonia) do not enhance aflatoxin (or sterigmatocystin) production at alkaline pH. RNA interference (in A. flavus) of the pH regulatory transcription factor, PacC, resulted in aflatoxin production under acidic and alkaline pH conditions whilst wildtype Aspergillus flavus produced aflatoxins only under acidic conditions. This conclusively proved that PacC negatively regulates aflatoxin production at alkaline pH in A. flavus. However the exact mechanism involved in PacC repression of aflatoxin biosynthesis at alkaline pH still remains unknown. The AflR protein is essential for expression of several genes in the aflatoxin biosynthetic cluster. In the current study, sequence analysis of the aflR promoter indicated the presence of two putative PacC binding sites within the aflR promoter of A. flavus 3357WT located at positions -162 and -487 bp from the start codon. The presence of the PacC binding sites in the aflR promoter indicated a possible link between aflR expression and PacC regulation under alkaline conditions. Thus, in this study, it was hypothesized that at alkaline pH, PacC inhibits aflR expression by binding to one or both of the PacC binding sites within the aflR promoter. This in turn, would result in inhibition of aflatoxin biosynthesis since expression of several aflatoxin biosynthetic pathway genes is dependent on activation by AflR. The aim and objective of this study was to test the validity of this hypothesis i.e. that at alkaline pH PacC binds to one or both of its recognition sites within the aflR promoter thereby inhibiting aflR expression which subsequently would result in inhibition of aflatoxin biosynthesis. This was done by first mutating each individual and then both PacC binding sites in the A. flavus 3357 aflR promoter via Single-Joint PCR (SJ-PCR) and fusing the wildtype and each mutated aflR promoter to the Green Fluorescent Protein (gfp) gene and the trpC terminator to yield a functional expression vector. These constructs were then transformed into A. flavus 3357.5. Positive transformants were confirmed to express GFP by fluorescence microscopy and spectrofluorometry. Quantification of GFP protein levels of the various transformants in this study indicated that PacC negatively regulated aflR promoter activity at alkaline pH. RT-qPCR was performed on positive transformants after growth on SLS medium at acidic and alkaline pH to determine if PacC negatively regulated aflR promoter activity at alkaline pH and to determine whether PacC binds preferentially to one or both recognition sites within the aflR promoter. RT-qPCR analysis suggest that PacC binds non-preferentially to both recognition sites within the aflR promoter on sucrose and lactose media at alkaline pH, although mutation of PacC binding site 2 results in a slightly higher expression compared to mutation of PacC binding site 1. Increasing the concentration of an aflatoxin conducive nitrogen source stimulated aflR promoter activity but this was not sufficient to overcome negative regulation by PacC. It is generally known that repression of aflR expression results in repression of aflatoxin biosynthesis irrespective of pH. The results of this study strongly suggest that PacC negatively regulates aflR promoter activity at alkaline pH by binding to one or both PacC recognition sites within the aflR promoter. Since aflR promoter activity is repressed by PacC at alkaline pH, this substantiates the hypothesis that PacC represses aflatoxin biosynthesis by inhibiting expression of aflR. Furthermore, the results of this study indicated that there may be some PacC protein present in the active form at acidic pH irrespective of the carbon source and nitrogen source used in the growth medium. RT-qPCR analysis indicated that any active PacC present at acidic pH may cause repression of the aflR promoter based on the position of the PacC binding site relative to the aflR start codon, although it appears that PacC may have a higher affinity for PacC binding site 2 (which is closer to the aflR start codon).