Engineering multicellular logic in bacteria with metabolic wires

Aromatic biodegradation pathways of environmental bacteria are vast sources of matching trios of enzymes, substrates and regulators that can be refactored to run logic operations through cell-to-cell communication. As a proof of concept, the connection between two Pseudomonas putida strains using benzoic acid as the wiring molecule is presented. In this system, a sender strain harboring the TOL pathway for biodegradation of aromatics processed toluene as input and generated benzoate as the output signal. Diffusion of such metabolic intermediate to the medium was then sensed by a second strain (the receiver) that used benzoate as input for a new logic gate producing a visual output (i.e., light emission). The setup was functional irrespective of whether sender and receiver cells were in direct contact or in liquid culture. These results highlight the potential of environmental metabolic pathways as sources of building blocks for the engineering of multicellular logic in prokaryotic systems. © 2013 American Chemical Society.This study was supported by the BIO and FEDER CONSOLIDER-INGENIO program of the Spanish Ministry of Science and Innovation, the MICROME, ST-FLOW and ARYSIS Contracts of the EU, and the PROMT Project of the Autonomous Community of Madrid.Peer Reviewe

Teoria da Argumentação Jurídica Aplicada à Atividade Jurisdicional

 Partindo da premissa de que o aplicador do Direito deve realizar juízos de valor, Alexy desenvolveu uma teoria da argumentação jurídica capaz de proporcionar respostas racionais para os problemas jurídicos. Isso aconteceria sempre que fosse seguido o procedimento descrito nas vinte e três regras do “discurso prático geral” (inspiradas na teoria do discurso habermasiana) e nas dezoito regras do “discurso jurídico”, que seria um caso especial do primeiro. Até para interpretar uma norma jurídica, isto é, escolher um entre os vários significados possíveis, o aplicador do Direito deveria argumentar, permitindo assim que os outros verifiquem se a sua interpretação está correta. Como os juízes têm o dever de fundamentar suas decisões, a teoria da argumentação jurídica pode ser útil à atividade jurisdicional, conferindo-lhe legitimidade democrátic

Transcriptional regulation of central carbon metabolism in Pseudomonas aeruginosa.

Microbes such as Pseudomonas aeruginosa are often challenged by rapidly changing nutritional environments. In order to adapt to these shifts in nutrient availability, bacteria exert tight transcriptional control over the enzymes of central metabolism. This transcriptional control is orchestrated by a series of transcriptional repressors and activators. Although a number of these transcription factors have been identified, many others remain uncharacterized. Here, we present a simple pipeline to uncover and validate the targets of uncharacterized transcriptional regulators in P. aeruginosa. We use this approach to identify and confirm that an orthologue of the Pseudomonas fluorescens transcriptional regulator (RccR) binds to the upstream region of isocitrate lyase (aceA) in P. aeruginosa, thereby repressing flux through the glyoxylate shunt during growth on non-C2 carbon sources

The private life of environmental bacteria: pollutant biodegradation at the single cell level

Bacteria display considerable cell-to-cell heterogeneity in a number of genetic and physiological traits. Stochastic differences in regulatory patterns (e.g., at the transcriptional level) propagate into the metabolic and physiological status of otherwise isogenic cells, which ultimately results in appearance of sub-populations within the community. As new technologies emerge and because novel single cell strategies are constantly being refined, our knowledge on microbial individuality is in burgeoning and constant expansion. These approaches encompass not only molecular biology tools (e.g., fluorescent protein based reporters) but also a suite of sophisticated, non-invasive technologies to gain insight into the metabolic state of individual cells. Defining the role of individual heterogeneities is thus instrumental for the population-level understanding of macroscopic processes, in both environmental and industrial setups. The present article reviews the state-of-the-art methodologies for the investigation of single bacteria at both the genetic and metabolic level, and places the application of currently available tools in the context of microbial ecology and environmental microbiology. As a case example, we examine the stochastic and multi-stable behaviour of the TOL-encoded pathway of Pseudomonas putida mt-2 for the biodegradation of aromatic compounds. Bet-hedging strategies and division of labour are considered as factors pushing forward the evolution of environmental microorganisms.This study was supported by the BIO and FEDER CONSOLIDER INGENIO Program of the Spanish Ministry of Science and Innovation, the MICROME, ST-FLOW and ARYSIS Contracts of the EU, the ERANET-IB Program and the PROMT Project of the CAM.Peer reviewe

Educação do campo na tríplice fronteira: a experiência de extensionistas em escolas de assentamentos rurais no Paraguai e Argentina.

Trabalho apresentado no II Seminário Nacional de Estudos e Pesquisas Sobre Educação do Campo e IV Jornada de Educação Especial no Campo, evento organizado pela Universidade Federal de São Carlos (UFSCAR).Buscar conhecer os desafios da educação rural na fronteira, uma região marcada pelo bilinguismo, pelo multiculturalismo e pela busca dos movimentos sociais por uma educação de qualidade que respeite suas necessidades e identidade e as políticas públicas voltadas para educação rural nestes países para poder compará-las com a realidade e as políticas públicas da educação do campo no Brasil e em especial da região embora abranja três países forma uma única região com alto nível de interdependência

Determining factors of domestic accidents in early childhood

Introduction: Domestic accidents are one of the main causes of death among children, characterized by an event that involves multiple determinants, emphasizing, among others, intrapersonal, interpersonal, cultural and institutional factors. Objective: To analyse the determinants of domestic accidents in early childhood. Methods: This is an exploratory, descriptive, and cross-sectional study carried out in the Emergency Hospital of Teresina city, Piauí, Brazil, between January and March 2016. The population was composed of 21 caregivers of children under five years old, hospitalized between January and March 2016. For data collection, a structured interview was conducted on aspects related to the risk factors associated with the incidence of domestic accidents involving children. A descriptive analysis was performed, with absolute and relative frequencies for the variables. The Human Research Ethics Committee approved the research with Protocol No. 1324184. Results: In relation to intrapersonal factors, pre-school children were the main victims (57.2%). For interpersonal factors, it was observed that most of participants (85.7%) considered the household unsafe for children. The evaluation of institutional factors showed that most caregivers (52.4%) had not been advised about the prevention of accidents at home. In  terms of cultural factors, most participants (81%) had not heard news about domestic accidents. Conclusion: Parents and caregivers have very limited knowledge about the prevention of childhood accidents at home, with male pre-schoolers the main victims of domestic accidents

The logic layout of the TOL network of Pseudomonas putida pWW0 plasmid stems from a metabolic amplifier motif (MAM) that optimizes biodegradation of m-xylene

<p>Abstract</p> <p>Background</p> <p>The genetic network of the TOL plasmid pWW0 of the soil bacterium <it>Pseudomonas putida </it>mt-2 for catabolism of <it>m-</it>xylene is an archetypal model for environmental biodegradation of aromatic pollutants. Although nearly every metabolic and transcriptional component of this regulatory system is known to an extraordinary molecular detail, the complexity of its architecture is still perplexing. To gain an insight into the inner layout of this network a logic model of the TOL system was implemented, simulated and experimentally validated. This analysis made sense of the specific regulatory topology out on the basis of an unprecedented network motif around which the entire genetic circuit for <it>m-</it>xylene catabolism gravitates.</p> <p>Results</p> <p>The most salient feature of the whole TOL regulatory network is the control exerted by two distinct but still intertwined regulators (XylR and XylS) on expression of two separated catabolic operons (<it>upper </it>and <it>lower</it>) for catabolism of <it>m</it>-xylene. Following model reduction, a minimal modular circuit composed by five basic variables appeared to suffice for fully describing the operation of the entire system. <it>In silico </it>simulation of the effect of various perturbations were compared with experimental data in which specific portions of the network were activated with selected inducers: <it>m-</it>xylene, <it>o-</it>xylene, 3-methylbenzylalcohol and 3-methylbenzoate. The results accredited the ability of the model to faithfully describe network dynamics. This analysis revealed that the entire regulatory structure of the TOL system enables the action an unprecedented metabolic amplifier motif (MAM). This motif synchronizes expression of the <it>upper </it>and <it>lower </it>portions of a very long metabolic system when cells face the head pathway substrate, <it>m-</it>xylene.</p> <p>Conclusion</p> <p>Logic modeling of the TOL circuit accounted for the intricate regulatory topology of this otherwise simple metabolic device. The found MAM appears to ensure a simultaneous expression of the <it>upper </it>and <it>lower </it>segments of the <it>m-</it>xylene catabolic route that would be difficult to bring about with a standard substrate-responsive single promoter. Furthermore, it is plausible that the MAM helps to avoid biochemical conflicts between competing plasmid-encoded and chromosomally-encoded pathways in this bacterium.</p