Streptomyces coelicolor Encodes a Urate-Responsive Transcriptional Regulator with Homology to PecS from Plant Pathogens

Many transcriptional regulators control gene activity by responding to specific ligands. Members of the multiple-antibiotic resistance regulator (MarR) family of transcriptional regulators feature prominently in this regard, and they frequently function as repressors in the absence of their cognate ligands. Plant pathogens such as Dickeya dadantii encode a MarR homolog named PecS that controls expression of a gene encoding the efflux pump PecM in addition to other virulence genes. We report here that the soil bacterium Streptomyces coelicolor also encodes a PecS homolog (SCO2647) that regulates a pecM gene (SCO2646). S. coelicolor PecS, which exists as a homodimer, binds the intergenic region between pecS and pecM genes with high affinity. Several potential PecS binding sites were found in this intergenic region. The binding of PecS to its target DNA can be efficiently attenuated by the ligand urate, which also quenches the intrinsic fluorescence of PecS, indicating a direct interaction between urate and PecS. In vivo measurement of gene expression showed that activity of pecS and pecM genes is significantly elevated after exposure of S. coelicolor cultures to urate. These results indicate that S. coelicolor PecS responds to the ligand urate by attenuated DNA binding in vitro and upregulation of gene activity in vivo. Since production of urate is associated with generation of reactive oxygen species by xanthine dehydrogenase, we propose that PecS functions under conditions of oxidative stress

Ideologia, fetiche e utopia na saúde: uma análise a partir da saúde bucal Ideology, fetish and utopia at oral health public policts

No artigo pretendemos caracterizar 3 conceitos essenciais para se compreender a produção de necessidades humanas, como a saúde, seu escalonamento na esfera de valores socialmente construídos e as relações de poder usualmente escondidas quando se trata do adoecer humano. Ao abordar o termo fetiche, tomamos o conceito de Marx sobre o fetichismo da mercadoria, e partimos então dessa perspectiva para caracterizar a expressão "fetichismo odontológico". Depois, fazemos uma reflexão sobre ideologia, um conceito carregado de historicidade e, por isso, polêmico. Partimos, entretanto, já da visão dialética marxista, quando Marx e Engels ressignificaram o que seria ideologia. Concluímos com uma análise do conceito de utopia, que consideramos, no sentido sociológico, a expressão de grupos contra-hegemônicos num movimento de crítica à ideologia. Focalizamos a "utopia da saúde bucal" como um movimento de construção de propostas alternativas com a finalidade de transformar a realidade. O objetivo é constituir uma base de conhecimento que, mesmo bastante limitada, permita analisar a realidade sob um ponto de vista alternativo àquele que estamos habituados, para que assim possamos compreender que o que se faz necessário não são mudanças em métodos ou instrumentos, nem em maneiras de agir, mas a compreensão de uma história mais real e menos natural.<br>The aim of this task is to discuss a new proposal of Collective (Public) Oral Health for the professional development of Brazilian dentists. This study is based in a new model of attention in oral health. The Collective Oral Health is a critical movement that is fighting for its own legitimation as public health politics and philosophic bases to dental schools against the hegemony. Fundamented in a analysis of social, cultural, political and economical contexts of contemporary Brazil, and based in a critical reflection of dental education, clinical practice of dentistry and some concepts like fetish, ideology and utopia, the study discuss the limitations that the present model of public politics employed brings to health promotion and life's quality for Brazilian society. Therefore we discuss the beginning of the movement and also analyzed some experiences in the organization of public health services. The project of collective oral health proposes changes in health attention and new compromises and political articulations for the reconstruction of the Brazilian society