Tuberculose e o estudo molecular da sua epidemiologia

Systems that can distinguish epidemiologically-related Mycobacterium tuberculosis strains from unrelated ones are extremely valuable. Molecular biology techniques have allowed a great deal of information to be acquired about the infectious disease tuberculosis (TB) that was very hard or impossible to obtain by conventional epidemiology. A typing method based on bacterial DNA genome differences, known as RFLP (restriction fragment length polymorphism), is widely used to discriminate strains in the epidemiologic study of TB. However, RFLP is laborious and there is a tendency to replace it by other methods. Thus, other DNA sequences have been employed as epidemiological markers, as in Spoligotyping, a fast technique based on PCR followed by differential hybridization of amplified products. The polymorphism observed among different isolates is probably the product of strain-dependent recombination. MIRU (mycobacterial interspersed repetitive unit) typing is a reproducible and fast assay, involving the generation of genotypes based on the study of 12 loci containing VNTRs (variable-number tandem repeats) in strains of the M. tuberculosis complex. It compares strains from different geographic areas and allows the movement of individual lineages to be tracked, as in RFLP. This approach enables a greater number of isolates to be analyzed, leading to the identification of a larger number of foci of transmission within the population and thus to improved ways of slowing the progress of the disease.

Comparison of three molecular typing methods to assess genetic diversity for Mycobacterium tuberculosis

This study describes the comparison of three methods for genotyping of Mycobacterium tuberculosis, namely MIRU-VNTR (mycobacterial interspersed repetitive units-variable number of tandem repeats), spoligotyping and, for the first time, MLST (Multilocus Sequence Typing). In order to evaluate the discriminatory power of these methods, a total of 44 M. tuberculosis isolates obtained from sputum specimens of patients from Brazil were genotyped. Among the three methods, MLST showed the lowest discriminatory power compared to the other two techniques. MIRU-VNTR showed better discriminatory power when compared to spoligotyping, however, the combination of both methods provides the greatest level of discrimination and therefore this combination is the most useful genotyping tool to be applied to M. tuberculosis isolates. © 2013 Elsevier B.V.

Screening of genomic libraries

Microsatellites, or simple sequence repeats (SSRs), have proven to be an important molecular marker in plant genetics and breeding research. The main strategies to obtain these markers can be through genomic DNA and from expressed sequence tags (ESTs) from mRNA/cDNA libraries. Genetic studies using microsatellite markers have increased rapidly because they can be highly polymorphic, codominant markers and they show heterozygous conserved sequences. Here, we describe a methodology to obtain microsatellite using the enrichment library of DNA genomic sequences. This method is highly efficient to development microsatellite markers especially in plants that do not have available ESTs or genome databases. This methodology has been used to enrich SSR marker libraries in Citrus spp., an important tool to genotype germplasm, to select zygotic hybrids, and to saturate genetic maps in breeding programs. © Springer Science+Business Media, LLC 2013.

Chromosomal Mapping of Repetitive DNAs in the Grasshopper Abracris flavolineata Reveal Possible Ancestry of the B Chromosome and H3 Histone Spreading

Supernumerary chromosomes (B chromosomes) occur in approximately 15% of eukaryote species. Although these chromosomes have been extensively studied, knowledge concerning their specific molecular composition is lacking in most cases. The accumulation of repetitive DNAs is one remarkable characteristic of B chromosomes, and the occurrence of distinct types of multigene families, satellite DNAs and some transposable elements have been reported. Here, we describe the organization of repetitive DNAs in the A complement and B chromosome system in the grasshopper species Abracris flavolineata using classical cytogenetic techniques and FISH analysis using probes for five multigene families, telomeric repeats and repetitive C0t-1 DNA fractions. The 18S rRNA and H3 histone multigene families are highly variable and well distributed in A. flavolineata chromosomes, which contrasts with the conservation of U snRNA genes and less variable distribution of 5S rDNA sequences. The H3 histone gene was an extensively distributed with clusters occurring in all chromosomes. Repetitive DNAs were concentrated in C-positive regions, including the pericentromeric region and small chromosomal arms, with some occurrence in C-negative regions, but abundance was low in the B chromosome. Finally, the first demonstration of the U2 snRNA gene in B chromosomes in A. flavolineata may shed light on its possible origin. These results provide new information regarding chromosomal variability for repetitive DNAs in grasshoppers and the specific molecular composition of B chromosomes. © 2013 Bueno et al.

The population genetic structure of Rhizoctonia solani AG-3PT from potato in the Colombian Andes

The soilborne fungus Rhizoctonia solani anastomosis group 3 (AG-3PT) is a globally important potato pathogen. However, little is known about the population genetic processes affecting field populations of R. solani AG-3PT, especially in the South American Colombian Andes, which is near the center of diversity of the two most common groups of cultivated potato, Solanum tuberosum and S. phureja. We analyzed the genetic structure of 15 populations of R. solani AG-3PT infecting potato in Colombia using 11 simple-sequence repeat (SSR) markers. In total, 288 different multilocus genotypes were identified among 349 fungal isolates. Clonal fractions within field populations were 7 to 33%. R ST statistics indicated a very low level of population differentiation overall, consistent with high contemporary gene flow, though moderate differentiation was found for the most distant southern populations. Genotype flow was also detected, with the most common genotype found widely distributed among field populations. All populations showed evidence of a mixed reproductive mode, including both asexual and sexual reproduction, but two populations displayed evidence of inbreeding. © 2013 The American Phytopathological Society.

Susceptibilidade antifúngica, produção de biofilme e caracterização do gene ALS3 em isolados de Candida albicans e não-albicans do hospital das clínicas, UNESP, Botucatu

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo de frequências alélicas de STRs do cromossomo X na população brasileira de Araraquara-SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação do emprego de um novo método de triagem molecular da síndrome do cromossomo X frágil em indivíduos brasileiros

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Blogs entre o continuum e o degradé: um estudo de gêneros ciberjornalísticos e critérios de noticiabilidade

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Educação ambiental e temas controversos: os conflitos socioambientais no contexto de um processo de formação continuada

Pós-graduação em Educação - IBRC

Isolamento e caracterização de marcadores de DNA associados ao sexo e segmentos de DNA repetitivo em espécies do gênero Brycon (Characidae, Bryconinae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo caso-controle em genes polimórficos das vias esteróide (ER-alfa e ER-beta) e da insulina (INSR, PA-1 e IGF2) na síndrome do ovário policístico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Verificação da formação de complexos protéicos nos telômeros de L. amazonensis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Caracterização da variabilidade genética em isolados de Xanthomonas albilineans oriundos de diferentes regiões do Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)