Homology modeling studies of beta(1,3)-D-glucan synthase of Moniliophthora perniciosa

The Witches' Broom Disease, caused by the hemibiotrophic basidiomycete fungus Moniliophthora perniciosa, drastically reduced the production of cocoa in Brazil. Phytosanitation, chemical control, genetically resistant strains, and biological control still leave flaws in the disease eradication process. Effort has been expended in the elucidation of molecular targets, in particular, the structural components of the fungal cell wall, such as the beta(1,3)-D-glucan synthase. This enzyme is essential for the cellular construction of the wall, as it catalyses the formation of beta(1,3)-D-glucans. Protein structure homology modeling approaches are able to determine the structure of proteins without performing experimental steps, considering the barriers related to experimental methods for the structural determination of molecular targets. The presence of the conserved catalytic residues in members of the same glycosyltransferase family and overall structural analysis suggests that they catalyze glycosyl transfer reactions by similar mechanisms. Therefore, the objective of this study was to determine the three-dimensional model of the enzyme beta(1,3)-D-glucan synthase of M. perniciosa by homology modeling. Both procedures were performed to build the models: a comparative modeling by satisfaction of spatial restraints in MODELLER and a modeling by assembly of rigid bodies in the SWISS-MODEL software. The models were elected based on analysis of the stereochemistry quality and a quantitative assessment of similarity from the obtained models and to templates. A reasonable structural model was obtained of the beta(1,3)-D-glucan synthase enzyme (BegS1). The BegS1 model showed two distinct a/beta domains, features of the inverting glycosyltransferase family, and the topology of the folded structure showed 7 beta-strands and 13 alpha-helices. The BegS1 model showed the presence of a catalytic cavity formed by the conserved aspartic acid residues (Asp326, 345, 353, and 354 DDxD motif) implicated in substrate binding and/or catalysis. In the BegS1 model, this cavity is near a loop region, as was observed in the GT-2 family structure. It is encouraging to find that the model for BegS1 agrees well with structures from the GT-2 enzyme family. (C) 2012 Wiley Periodicals, Inc.11220SI3356336

Estrutura e organização do trabalho do cirurgião-dentista no PSF de municípios do Rio Grande do Norte Structure and organization of the work of dentists in the Family Health Program of some Municipal Districts of Rio Grande do Norte (Brazil)

Esta investigação tem como objetivo analisar o perfil de atuação de cirurgiões-dentistas inseridos no Programa de Saúde da Família (PSF) de municípios do Rio Grande do Norte, buscando conhecer e compreender a experiência de trabalho que estes profissionais desenvolvem no Programa. A população integrante da pesquisa foi composta de cirurgiões-dentistas PSF do Rio Grande do Norte. Foram realizadas 21 entrevistas orientadas por um roteiro semi-estruturado, com perguntas abertas e composta de dados de identificação. Optou-se por gravar a fala dos profissionais, tendo em vista uma melhor fidelidade da coleta de informações. Os principais resultados encontrados foram: predominância do sexo feminino; maioria dos entrevistados sem pós-graduação, verificando-se, entre seus portadores, a falta de relação entre o referido curso e a saúde pública ou coletiva; os cirurgiões-dentistas têm perfil voltado para a atividade clínica; estes profissionais desenvolviam atividades básicas de dentística, periodontia básica, cirurgia simples e atividades preventivas e educativas, embora realizadas de maneira tradicional (palestras e aplicação de flúor). Os resultados apontam que há necessidade de motivá-los a refletir e redirecionar as suas práticas, tendo como medida inicial o investimento e estímulo à educação permanente e um monitoramento e avaliação das ações desenvolvidas.<br>The purpose of this research was to analyze the working profile of dentists from the Family Health Program of some Municipal Districts of Rio Grande do Norte (Brazil) in order to understand the way they handle the experience acquired with the work developed in that Program. The target population was composed of dentists from the FHP of Rio Grande do Norte. Thus we performed 21 interviews orientated by a semi-structured guidebook with open questions and identification data, beyond recording the speech of all the professionals. The main results found were: predominance in the female gender; the majority of dentists has no post graduation courses; in those few cases of dentists with some post-graduation a lack of correlation with Public or Collective Health was observed; the dentists interviewed present a profile directed to clinical activities; the dentists used to develop basic conducts and educative and preventive activities, even though the last two ones are carried out in an extremely traditional way (lectures and topical application of fluoride). The results indicate the existence of a necessity to lead them to reflect and redirect their practices. In order to reach this aim it must be considered as initial measure the investment and encouragement toward to permanent education as well as a close follow-up and evaluation of the actions developed by them