Importance of Bacillithiol in the Oxidative Stress Response of Staphylococcus aureus

In Staphylococcus aureus, the low-molecular-weight thiol called bacillithiol (BSH), together with cognate S-transferases, is believed to be the counterpart to the glutathione system of other organisms. To explore the physiological role of BSH in S. aureus, we constructed mutants with the deletion of bshA (sa1291), which encodes the glycosyltransferase that catalyzes the first step of BSH biosynthesis, and fosB (sa2124), which encodes a BSH-S-transferase that confers fosfomycin resistance, in several S. aureus strains, including clinical isolates. Mutation of fosB or bshA caused a 16- to 60-fold reduction in fosfomycin resistance in these S. aureus strains. High-pressure liquid chromatography analysis, which quantified thiol extracts, revealed some variability in the amounts of BSH present across S. aureus strains. Deletion of fosB led to a decrease in BSH levels. The fosB and bshA mutants of strain COL and a USA300 isolate, upon further characterization, were found to be sensitive to H2O2 and exhibited decreased NADPH levels compared with those in the isogenic parents. Microarray analyses of COL and the isogenic bshA mutant revealed increased expression of genes involved in staphyloxanthin synthesis in the bshA mutant relative to that in COL under thiol stress conditions. However, the bshA mutant of COL demonstrated decreased survival compared to that of the parent in human whole-blood survival assays; likewise, the naturally BSH-deficient strain SH1000 survived less well than its BSH-producing isogenic counterpart. Thus, the survival of S. aureus under oxidative stress is facilitated by BSH, possibly via a FosB-mediated mechanism, independently of its capability to produce staphyloxanthin

Acima dos confrontos sobre os transgênicos: uma experiência piloto de consulta pública.

RESUMO: A tecnologia do DNA recombinante abriu, juntamente com um horizonte ilimitado de possibilidades de inovações, polêmicas que não podem ser ignoradas ou resolvidas por meio de uma difusão linear de informações. Ações multidisciplinares e multi-institucionais têm sido implementadas, com sucesso, em diversos países, para estabelecer novas formas de comunicação entre peritos e leigos. Isso permite identificar possíveis restrições e benefícios nas trajetórias tecnológicas, e assim entender e negociar eventuais conflitos. No Brasil, esse tipo de abordagem não tem recebido atenção significativa. A metodologia Problem Formulation and Options Assessment (PFOA), articulada no contexto do projeto internacional Genetically Modified Organisms - Environmental Risk Assessment (GMO-ERA), e sintonizada com as novas tendências de envolvimento dos diversos setores de interesse (stakeholders) ligados a uma tecnologia, propõe integrar na análise de risco as perspectivas ambiental, social, econômica e ética. A equipe de implementação de uma experiência piloto do PFOA foi formada pelo grupo do GMOERA - ligado ao Projeto Rede de Biossegurança (BioSeg), da Empresa Brasileira de Pesquisa Agropecuária (Embrapa), pelo Instituto de Pesquisa em Riscos e Sustentabilidade, da Universidade Federal de Santa Catarina (Iris-UFSC), e pelo Centro de Gestão de Estudos Estratégicos do Ministério da Ciência e Tecnologia (CGEE/MCT). O caso utilizado como modelo foi o feijão geneticamente modificado resistente ao mosaico-dourado, que vem sendo desenvolvido pela Embrapa. O piloto, financiado pelo CGEE/MCT, contou com a participação de diversos stakeholders. Dentre as conclusões, recomenda-se o uso de sistemas de informação não unidirecionados, mais transparentes e abertos, baseados em uma ciência rigorosa, para subsidiar as instâncias científicas e políticas nas tomadas de decisão. abstract: Recombinant DNA technology, together with an unlimited horizon of possibilities of innovation, triggered a discussion, among stakeholders, that cannot be ignored or solved through a linear difusion of information. Multidisciplinary and multi-institutional actions are being successfully adopted in several countries to establish new communication strategies between specialists and stakeholders. These strategies allow the identification of possible constraints and benefits of a technology during its development and, consequently, understanding and negotiation of conflicts. In Brazil this approach is not being used yet. The Problem Formulation and Options Assessment (PFOA) methodology was proposed by the Genetically Modified Organisms - Environmental Risk Assessment (GMO-ERA) project, aligned with the new trend of involving stakeholders in the risk assessment of a new technology. PFOA integrates the environmental, social, economic and ethical perspectives into the risk assessment of a technology. PFOA's pilot experience was conducted by a group formed by the GMO-ERA team associated with the Biosafety Network (BioSeg) project of the Brazilian Agricultural Research Corporation (Embrapa), by the Institute of Research in Risk and Sustainability from the Federal University of Santa Catarina (Iris-UFSC) and by the Center for Strategic Management and Studies in Science, Technology and Innovation of the Ministry of Science and Technology (CGEE/ MCT). The case study was a genetically modified bean resistant to the golden mosaic disease, which is being developed by Embrapa. This pilot was funded by CGEE/MCT and gathered representatives of several stakeholders. It could be concluded that the use of non-directed, transparent, open and science-based communication approaches is of great value for scientific and political decision making instances

Doing Research Through Descriptions of Teachers

The idea that teaching is a complex set of practices, deep-rooted in teachers\u2019 personal \u201cbeing-in-the-world\u201d, underlies this research which employs a phenomenological approach in order to gain an indepth understanding of the teaching experience as it is perceived and thought of by those who are personally involved in it. The research objectives involve both methodological reflection on and knowledge development of teachers\u2019 experience. Qualitative conversational interview is the research technique we have used. This reflection originates from a two-year study of teachers\u2019 knowledge about practice: thirty-five teachers were involved each one of whom was interviewed twice. The analysis of the interviews has led to a complex vision of teaching practice, seen from the teachers\u2019 viewpoint. The core of their descriptions concerns several different meanings, expressed by all the teachers of all school grades, creating a composite profile of what teachers consider as essential in their practice. The data analysis led to the recognition of the presence of two main areas of teachers' practice. A research on the meanings teachers develop about their practice can be significant at two different levels: i. methodological; ii. About practical knowledge in schoolwork

Biofortificação no Brasil (BioFort): Avaliação preliminar de clones de batata-doce ricos em betacaroteno.

Com o objetivo de disponibilizar aos agricultores e, por conseguinte aos consumidores, cultivares de batata-doce com melhores teores de betacaroteno, a Embrapa realiza seleçaõ de clones no âmbito do programa BioFORT: Biofortificação no Brasil - desenvolvendo produtos agricolas mais nutritivos, que tem por finalidade desenvolver alimentos naturais com quantidades de nutrientes capazes de suprir a necessidade nutricional do corpo humano. O objetivo deste trabalho é apresentar os resultados obtidos numa avaliação prelimar de 96 clones de batata-doce de polpa amarela e alaranjada, e identificar os promissores para avaliações subsequentes em difeentes regiões.CD-ROM. Suplemento. Trabalho apresentado no 51. Congresso Brasileiro de Olericultura, Viçosa, MG

Doing Research through Descriptions of Teachers

The idea that teaching is a complex set of practices, deep-rooted in teachers\u2019 personal \u201cbeing-in-the-world\u201d, underlies this research which employs a phenomenological approach in order to gain an indepth understanding of the teaching experience as it is perceived and thought of by those who are personally involved in it. The research objectives involve both methodological reflection on and knowledge development of teachers\u2019 experience. Qualitative conversational interview is the research technique we have used. This reflection originates from a two year study of teachers\u2019 knowledge about practice: thirty-five teachers were involved each one of whom was interviewed twice. The analysis of the interviews has led to a complex vision of teaching practice, seen from the teachers\u2019 viewpoint. The core of their descriptions concerns several different meanings, expressed by all the teachers of all school grades, creating a composite profile of what teachers consider as essential in their practice. The data analysis led to the recognition of the presence of two main areas of teachers' practice. A research on the meanings teachers develop about their practice can be significant at two different levels: i. methodological; ii. About practical knowledge in schoolwor

Susceptibility of common and tepary beans to Agrobacterium spp. strains and improvement of Agrobacterium-mediated transformation using microprojectile bombardment.

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Elastic constant dishomogeneity and Q2Q^2 dependence of the broadening of the dynamical structure factor in disordered systems

We propose an explanation for the quadratic dependence on the momentum $Q$, of the broadening of the acoustic excitation peak recently found in the study of the dynamic structure factor of many real and simulated glasses. We ascribe the observed $Q^2$ law to the spatial fluctuations of the local wavelength of the collective vibrational modes, in turn produced by the dishomegeneity of the inter-particle elastic constants. This explanation is analitically shown to hold for 1-dimensional disordered chains and satisfatorily numerically tested in both 1 and 3 dimensions.Comment: 4 pages, RevTeX, 5 postscript figure