High-quality genome-scale metabolic modelling of \u3ci\u3ePseudomonas putida\u3c/i\u3e highlights its broad metabolic capabilities

Genome-scale reconstructions of metabolism are computational species-specific knowledge bases able to compute systemic metabolic properties. We present a comprehensive and validated reconstruction of the biotechnologically relevant bacterium Pseudomonas putida KT2440 that greatly expands computable predictions of its metabolic states. The reconstruction represents a significant reactome expansion over available reconstructed bacterial metabolic networks. Specifically, iJN1462 (i) incorporates several hundred additional genes and associated reactions resulting in new predictive capabilities, including new nutrients supporting growth; (ii) was validated by in vivo growth screens that included previously untested carbon (48) and nitrogen (41) sources; (iii) yielded gene essentiality predictions showing large accuracy when compared with a knock-out library and Bar-seq data; and (iv) allowed mapping of its network to 82 P. putida sequenced strains revealing functional core that reflect the large metabolic versatility of this species, including aromatic compounds derived from lignin. Thus, this study provides a thoroughly updated metabolic reconstruction and new computable phenotypes for P. putida, which can be leveraged as a first step toward understanding the pan metabolic capabilities of Pseudomonas

Identification and characterization of the PhhR regulon in Pseudomonas putida

Pseudomonas putida is a soil microorganism that utilizes aromatic amino acids present in root exudates as a nitrogen source. We have previously shown that the PhhR transcriptional regulator induces phhAB genes encoding a phenylalanine hydroxylase. In this study we show, using microarray assays and promoter fusions, that PhhR is a global regulator responsible for the activation of genes essential for phenylalanine degradation, phenylalanine homeostasis and other genes of unknown function. Recently, it has been shown that phenylalanine catabolism occurs through more than one pathway. One of these possible pathways involves the metabolism of phenylalanine via tyrosine, p-hydroxyphenylpyruvate, and homogentisate. We identified two genes within this pathway that encode an acyl-CoA transferase involved in the metabolism of acetoacetate. All genes in this pathway were induced in response to phenylalanine in a PhhR-proficient background. The second potential degradative pathway involves the degradation of phenylalanine to produce phenylpyruvate, which seems to be degraded via phenylacetyl-CoA. A number of mutants in the paa genes encoding phenylacetyl-CoA degradation enzymes fail to grow on phenylpyruvate or phenylacetate, further supporting the existence of this second pathway. We found that the PhhR regulon also includes genes involved in the biosynthesis of aromatic amino acids that are repressed in the presence of phenylalanine, suggesting the possibility of feedback at the transcriptional level. In addition, we found that PhhR modulates the level of expression of the broad-substrate-specificity MexEF/OprN efflux pump. Expression from this pump is under the control of mexT gene product because phenylalanine-dependent transcription from the mexE promoter does not occur in a mexT mutant background. These results place PhhR as an important regulator in the control of bacterial responses to aromatic amino acids

Promoção da saúde: O renascimento de uma ideologia?

A concepção actual de promoção de saúde, educação para a saúde e prevenção da doença é suportada por ideologias algo adulteradas pela realidade social. Tendo em conta a proliferação epistemológica destes conceitos no final do século XX pretende-se, no presente artigo, elaborar uma reflexão crítica em torno das múltiplas racionalidades estratégicas em que os conceitos se organizam, bem como, abordar os paradoxos que se instalam ao nível dos determinantes biopsicossociais dos comportamentos salutogénicos. Partilhando responsabilidades, os profissionais de saúde, devem, colectiva e proactivamente, desempenhar um papel significativo como promotores de saúde, modelando e reforçando o significado “leigo” dos comportamentos, para que se possam incrementar mudanças efectivas em segmentos alargados da população.The nowadays’ notion of health promotion, health education and prevention is supported by ideologies, which are somehow changed by social reality. Bearing in mind the epistymological growth of these concepts occurred in the end of the XXth century, it is our purpose, with the present article, to develop a critical reflection on the several strategical racionalities in which concepts are organised, as well as to broach the paradoxes, which establish themselves at the level of biopsychosocial determinants of health behaviours. Sharing responsabilities, the health care professionals must, collective and proactively, play an important role as health promotors, as they shape and reinforce the “common” meaning of behaviours, so that efective changes may increase in large segments of the population.info:eu-repo/semantics/publishedVersio

Promoção da saúde: O renascimento de uma ideologia?

A concepção actual de promoção de saúde, educação para a saúde e prevenção da doença é suportada por ideologias algo adulteradas pela realidade social. Tendo em conta a proliferação epistemológica destes conceitos no final do século XX pretende-se, no presente artigo, elaborar uma reflexão crítica em torno das múltiplas racionalidades estratégicas em que os conceitos se organizam, bem como, abordar os paradoxos que se instalam ao nível dos determinantes biopsicossociais dos comportamentos salutogénicos.Partilhando responsabilidades, os profissionais de saúde, devem, colectiva e proactivamente, desempenhar um papel significativo como promotores de saúde, modelando e reforçando o significado “leigo” dos comportamentos, para que se possam incrementar mudanças efectivas em segmentos alargados da população

Mejoramiento de la calidad en la carne de la trucha arcoíris mediante la técnica de sacrificio Ikejime: caso Ecuador

Las técnicas de sacrificio empleadas tradicionalmente en la industria pesquera provocan niveles altos de estrés en los peces debido a la violencia del proceso. Esta condición influye en la calidad de su carne. Con estos antecedentes, se identifica la técnica de sacrificio más adecuada para preparaciones culinarias mediante una evaluación sensorial para los atributos de olor, sabor y textura que permita potenciar esa calidad. Según las referencias recopiladas de carácter empírico, la técnica Ikejime, de origen japonés, es la más idónea para sacrificar peces. Las características gastronómicas de la carne de los que fueron pescados por este medio son superiores respecto a los que no. Las pruebas realizadas comprobaron dichas aseveraciones

Specific Gene Loci of Clinical Pseudomonas putida Isolates

Pseudomonas putida are ubiquitous inhabitants of soils and clinical isolates of this species have been seldom described. Clinical isolates show significant variability in their ability to cause damage to hosts because some of them are able to modulate the host’s immune response. In the current study, comparisons between the genomes of different clinical and environmental strains of P. putida were done to identify genetic clusters shared by clinical isolates that are not present in environmental isolates. We show that in clinical strains specific genes are mostly present on transposons, and that this set of genes exhibit high identity with genes found in pathogens and opportunistic pathogens. The set of genes prevalent in P. putida clinical isolates, and absent in environmental isolates, are related with survival under oxidative stress conditions, resistance against biocides, amino acid metabolism and toxin/antitoxin (TA) systems. This set of functions have influence in colonization and survival within human tissues, since they avoid host immune response or enhance stress resistance. An in depth bioinformatic analysis was also carried out to identify genetic clusters that are exclusive to each of the clinical isolates and that correlate with phenotypical differences between them, a secretion system type III-like was found in one of these clinical strains, a determinant of pathogenicity in Gram-negative bacteria.Work in the authors’ laboratories was supported by ERANET Pathogenomics programme through the ADHERS project (Ref: BIO2008-04419-E) and Fondos FEDER from the European Union through project BIO2010-17227 of the Ministry of Economy and Competitivity of Spain. Bio-Iliberis R&D provided supportPeer reviewe

Analysis of the pathogenic potential of nosocomial Pseudomonas putida strains

Pseudomonas putida strains are ubiquitous in soil and water but have also been reported as opportunistic human pathogens capable of causing nosocomial infections. In this study we describe the multilocus sequence typing of four P. putida strains (HB13667, HB8234, HB4184 and HB3267) isolated from in-patients at the Besançon Hospital (France). The four isolates (in particular HB3267) were resistant to a number of antibiotics. The pathogenicity and virulence potential of the strains was tested ex vivo and in vivo using different biological models: human tissue culture, mammalian tissues and insect larvae. Our results showed a significant variability in the ability of the four strains to damage the host; HB13667 did not exhibit any pathogenic traits, HB4184 caused damage only ex vivo in human tissue cultures, and HB8234 had a deleterious effect in tissue culture and in vivo on rat skin, but not in insect larvae. Interestingly, strain HB3267 caused damage in all the model systems studied. The putative evolution of these strains in medical environments is discussed

Analysis of the pathogenic potential of nosocomial Pseudomonas putida strains

The Supplementary Material for this article can be found online at: http://journal.frontiersin.org/article/10.3389/fmicb.2015.00871Pseudomonas putida strains are ubiquitous in soil and water but have also been reported as opportunistic human pathogens capable of causing nosocomial infections. In this study we describe the multilocus sequence typing of four P. putida strains (HB13667, HB8234, HB4184, and HB3267) isolated from in-patients at the Besançon Hospital (France). The four isolates (in particular HB3267) were resistant to a number of antibiotics. The pathogenicity and virulence potential of the strains was tested ex vivo and in vivo using different biological models: human tissue culture, mammalian tissues, and insect larvae. Our results showed a significant variability in the ability of the four strains to damage the host; HB13667 did not exhibit any pathogenic traits, HB4184 caused damage only ex vivo in human tissue cultures, and HB8234 had a deleterious effect in tissue culture and in vivo on rat skin, but not in insect larvae. Interestingly, strain HB3267 caused damage in all the model systems studied. The putative evolution of these strains in medical environments is discussed.Work in this study was supported by the ERANET Pathogenomics Program through the ADHERS-Signature Project (reference: BIO2008-04419-E)Peer reviewe

Physiological and transcriptomic characterization of a fliA mutant of Pseudomonas putida KT2440

Pseudomonas putida KT2440 encodes 23 alternative sigma factors. The fliA gene, which encodes σ28, is in a cluster with other genes involved in flagella biosynthesis and chemotaxis. Reverse transcriptase-PCR revealed that this cluster is comprised of four independent transcriptional units: flhAF, fleNfliA, cheYZA and cheBmotAB. We generated a nonpolar fliA mutant by homologous recombination and tested its motility, adhesion to biotic and abiotic surfaces, and responses to various stress conditions. The mutant strain was nonmotile and exhibited decreased capacity to bind to corn seeds, although its ability to colonize the rhizosphere of plants was unaffected. The mutant was also affected in binding to abiotic surfaces and its ability to form biofilms decreased by almost threefold. In the fliA mutant background expression of 25 genes was affected: two genes were upregulated and 23 genes were downregulated. In addition to a number of motility and chemotaxis genes, the fliA gene product is also necessary for the expression of some genes potentially involved in amino acid utilization or stress responses; however, we were unable to assign specific phenotypes linked to these genes since the fliA mutant used the same range of amino acids as the parental strain, and was as tolerant as the wild type to stress imposed by heat, antibiotics, NaCl, sodium dodecyl sulfate, H2O2 and benzoate. Based on the sequence alignment of promoters recognized by FliA and genome in silico analysis, we propose that P. putidaσ28 recognizes a TCAAG-t-N12-GCCGATA consensus sequence located between −34 and −8 and that this sequence is preferentially associated with an AT-rich upstream region