Overexpression of Phosphoenolpyruvate carboxykinase - cytosolic (PEPCK, encoded by Pck-1 gene) has been found to be associated with the prevalence of hyperglycemia in Type 2 Diabetes Mellitus (T2DM) patients. The Pck-1 enzyme catalyzes the rate limiting step in endogenous glucose production. The aims of this study are to develop a Pck-1:eGFP reporter zebrafish and validate it as a potential tool for the screening of novel anti-diabetic compounds. 3.6 kb zebrafish Pck-1 promoter fragment was cloned and a Pck-1:eGFP expression vector was constructed. After DNA microinjection, we generated Pck-1:eGFP reporter zebrafish with strong eGFP expression in developing liver. Validation studies confirmed that Pck-1:eGFP zebrafish embryos responded to treatment of glucose, cAMP and dexamethasone, metformin and rosiglitazone similarly to that of humans. This novel Pck-1:eGFP reporter fish line can serve as a tool for the screening and development of novel anti-diabetic drugs that may have potential in the treatment of T2DM.

Overexpression of Phosphoenolpyruvate carboxykinase - cytosolic (PEPCK, encoded by Pck-1 gene) has been found to be associated with the prevalence of hyperglycemia in Type 2 Diabetes Mellitus (T2DM) patients. The Pck-1 enzyme catalyzes the rate limiting step in endogenous glucose production. The aims of this study are to develop a Pck-1:eGFP reporter zebrafish and validate it as a potential tool for the screening of novel anti-diabetic compounds. 3.6 kb zebrafish Pck-1 promoter fragment was cloned and a Pck-1:eGFP expression vector was constructed. After DNA microinjection, we generated Pck-1:eGFP reporter zebrafish with strong eGFP expression in developing liver. Validation studies confirmed that Pck-1:eGFP zebrafish embryos responded to treatment of glucose, cAMP and dexamethasone, metformin and rosiglitazone similarly to that of humans. This novel Pck-1:eGFP reporter fish line can serve as a tool for the screening and development of novel anti-diabetic drugs that may have potential in the treatment of T2DM.

No description available.

Cílem práce je seznámení se s problematikou uchovávání informace v DNA, provést rešerši na téma transpozony, bioinformatické nástroje a algoritmy, které jsou používány k jejich detekci v nasekvenovaných genomech a vytvořit tak stručný úvod do obsáhle problematiky, včetně jejího zasazení do kontextu současně probíhajícího výzkumu v dané oblasti. Na základě přehledu stávajících algoritmů a nástrojů pro detekci transpozonů je navržen a implementován nástroj pro hledání tzv. LTR transpozonů.

No description available.

Bacillus amyloliquenaciense FZB42 ist ein bekanntes Pflanzenwachstum-stimulierendes Rhizobakterium. Es produziert neben einer Vielzahl an Sekundärmetaboliten mit antibakterieller und antifungaler Wirkung, auch das Pflanzenhormon IAA. Obwohl viele dieser Mechanismen diskutiert werden, ist wenig darüber bekannt, auf welche Weise die Bakterien das Pflanzenwachstum fördern. In dieser Arbeit wurde eine Transposonmutagenese mithilfe des ‘mariner-transposons’ durchgeführt, und so eine Transposonbibliothek erstellt. Diese wurde dann auf geeignete Phänotypen untersucht, um die Gene zu finden, welche bestimmte Phänotypen verursachen. So konnten drei Mutanten erzeugt werden, die auf Grund der gestörten Biofilmbildung und der Fähigkeit zu schwärmen die Pflanzenwurzeln nicht mehr kolonialisieren konnten. Eine solche degU-Mutante, welche in der Biofilmbildung und ‚Swarming’ defizitär war und zwei Mutanten (yusV und pabB), die eine Beeinträchtigung in der Biofilmbildung aufwiesen, konnten durch Komplementation und Retransformation bestätigt werden. Mithilfe des Lemna-Biosystems und anderer Analysen mit A. thaliana konnten drei Gene bei B. amyloliqufaciens FZB42 gefunden werden, die wichtig für die Förderung des Pflanzenwachstums sind. Koloniesierungsexperimente der Wurzeln von A. thaliana mit diesen Mutanten zeigten deutlich verändertes Wachstum, verglichen mit dem Wildtypstamm. Ein weiteres Ziel dieser Arbeit war es neue Antibiotika in Mutanten, die in ihren nicht-ribosomalen Synthesen blockiert sind, zu finden. So konnten durch die Untersuchungen der Transposonbibliothek der Mutanten zwei neue Antibiotika entdeckt werden. Genauere Analysen dieser Antibiotika bestätigten, dass es sich um ein neues Bacteriocin (Amylocyclicin A) und ein neues Thiazol/Oxazole-modifiziertes Microcin (Plantazolicin) handelt. Die abschließenden Arbeiten beschäftigten sich dann mit Untersuchungen von Genen, welche für die Produktion von Substanzen gegen Nematoden verantwortlich sind. Hierbei konnten vier Mutanten gefunden werden, die durch eine Transposoninsertion eine schlechtere. / Bacillus amyloliqufaciens FZB42 has been known as PGPR which has an impressive effect to improve plant growth. It produces not only vast array of secondary metabolites with antibacterial and antifungal activities, but also produces the plant hormone IAA. Although many mechanisms have been elucidated, our knowledge about basic molecular mechanisms responsible for its beneficial action is far from complete. In this study, transposon mutagenesis based on mariner tranposon was applied to generate tranposon library which then was screened to identify the genes involved in plant growth-promoting activity. Three mutants that were impaired in their ability to colonize plant surface due to defects in biofilm formation and swarming motility were found. One mutant (degU mutant) showed defect in biofilm formation and swarming motility, as well, two mutants (yusV mutant and pabB mutant) impaired in biofilm formation were confirmed by complementation and retransformation. Screening by the Lemna biosystem and further assays with A. thaliana revealed three genes responsible for reduction in plant growth promoting activity of B. amyloliqufaciens FZB42. Colonization studies of these mutants in A. thaliana roots revealed patterns different to the wild type. A further issue pursued in this study was to discover new antibiotics using a mutant which has been blocked in its nonribosomally pathway. Screening of tranposon librabries from this mutant led to the finding of two novel ribosomally synthesized antibiotics. Further characterization revealed that these new antibiotics belonged to a novel bacteriocin (Amylocyclicin A) and a novel thiazole/oxazole-modified microcin (Plantazolicin). Last work in this study was looking for genes responsible for nematocidal production. Four mutants which showed reduction in nematocidal activity due to transposon insertion were found.

Le genre bactérien Salmonella regroupe plus de 2500 sérovars, mais peu sont responsables de pathologies humaines. Salmonella enterica sérovar Typhi (S. Typhi) est reconnu pour son importance médicale à travers le globe. S. Typhi cause la fièvre typhoïde chez l’Homme, une maladie infectieuse létale caractérisée par la dissémination systémique de la bactérie vers des organes du système réticulo-endothélial. La fièvre typhoïde représente un fardeau pour la santé mondiale, notamment auprès des pays en développement où les conditions sanitaires sont désuètes. La situation se complique davantage par l’apparition de souches résistantes aux antibiotiques. De plus, les deux vaccins licenciés sont d’efficacité modérée, présentent certaines contraintes techniques et ne sont pas appropriés pour les jeunes enfants et nourrissons. La phase systémique de l’infection par Salmonella repose sur sa survie dans les macrophages du système immunitaire. Dans ce compartiment intracellulaire, la bactérie module les défenses antimicrobiennes grâce à de multiples facteurs de virulence encodés dans son génome. Les mécanismes moléculaires sollicités sont complexes et finement régulés. Malgré les progrès scientifiques réalisés précédemment, plusieurs incompréhensions persistent au sujet de l’adaptation de ce pathogène dans les macrophages de l’hôte. Pour mieux concevoir les déterminants génétiques de S. Typhi impliqués dans l’interaction avec ces cellules, une stratégie de sélection négative a été appliquée afin de vérifier systématiquement l’effet direct des gènes pendant l’infection. En premier temps, une librairie de mutants par transposon chez S. Typhi a été créée pour l’infection de macrophages humains en culture. Après 24 heures d’infection, la présence des mutants fut évaluée simultanément par analyse sur des biopuces de Salmonella. Au total, 130 gènes ont été sélectionnés pour leur contribution potentielle auprès des macrophages infectés. Ces gènes comptaient des composantes d’enveloppe bactérienne, des éléments fimbriaires, des portions du flagelle, des régulateurs, des facteurs de pathogenèse et plusieurs protéines sans fonction connue. En deuxième temps, cette collection de gènes a dirigé la création de 28 mutants de délétion définie chez S. Typhi. Les capacités d’entrée et de réplication intracellulaire de ces mutants au sein des macrophages humains ont été caractérisées. D’abord, les macrophages ont été co-infectés avec les mutants en présence de la souche sauvage, pour vérifier la compétitivité de chacun d’eux envers cette dernière. Ensuite, les mutants ont été inoculés individuellement chez les macrophages et leur infectivité fut mesurée comparativement à celle de la souche sauvage. Sommairement, 26 mutants ont présenté des défauts lorsqu’en compétition, tandis que 14 mutants se sont montrés défectueux lorsque testés seuls. Par ailleurs, 12 mutants ont exposé une déficience lors de l’infection mixte et individuelle, incluant les mutants acrA, exbDB, flhCD, fliC, gppA, mlc, pgtE, typA, waaQGP, STY1867-68, STY2346 et SPI-4. Notamment, 35 nouveaux phénotypes défectueux d’entrée ou de survie intracellulaire chez Salmonella ont été révélés par cette étude. Les données générées ici offrent plusieurs nouvelles pistes pour élucider comment S. Typhi manipule sa niche intracellulaire, menant à l’infection systémique. Les gènes décrits représentent des cibles potentielles pour atténuer la bactérie chez l’humain et pourraient contribuer au développement de meilleures souches vaccinales pour immuniser contre la fièvre typhoïde. / The bacterial genus Salmonella holds over 2500 serovars, but few are responsible for human pathologies. Salmonella enterica serovar Typhi (S. Typhi) is recognized across the globe for its medical importance. S. Typhi causes typhoid fever in humans, a lethal infectious disease characterized by systemic dissemination of the bacteria to organs of the reticulo-endothelial system. Typhoid fever represents a burden for public health, notably in developing countries where sanitary conditions are obsolete. The situation is further complicated by the appearance of strains resistant to antibiotics. Moreover, both of the licensed vaccines are of moderate efficiency, present certain technical constraints and are not appropriate for young children and newborns. The systemic phase of infection by Salmonella relies on its survival within macrophages of the immune system. In this intracellular compartment, the bacterium modulates antimicrobial defenses thanks to multiple virulence factors encoded within its genome. Molecular mechanisms taking place are complex and finely regulated. Despite scientific advances made previously, many misunderstandings persist concerning the adaptation of this pathogen within host macrophages. To better conceive the genetic determinants of S. Typhi involved in interaction with these cells, a negative selection strategy was applied to systematically verify the direct effect of genes during infection. Firstly, a library of transposon insertion mutants in S. Typhi was created for infection of cultured human macrophages. After 24 hours of infection, the presence of mutants was evaluated simultaneously by analysis on Salmonella microarrays. In total, 130 genes were selected for their potential contribution within infected macrophages. These genes included bacterial envelope components, fimbrial elements, portions of the flagellum, regulators, pathogenesis factors, and many proteins of unknown function. Secondly, this collection of genes led to the creation of 28 defined deletion mutants in S. Typhi. The ability of entry and intracellular replication of these mutants within human macrophages were characterized. To start, macrophages were coinfected with mutants in the presence of the wild-type strain, in order to verify the competitiveness of each of them against the latter. Then, mutants were inoculated individually into macrophages and their infectiveness was measured in comparison with the wild-type strain. In summary, 26 mutants presented defects when in competition, whereas 14 mutants were shown defective when tested alone. Furthermore, 12 mutants exposed a deficiency during mixed and individual infection experiments, including mutants acrA, exbDB, flhCD, fliC, gppA, mlc, pgtE, typA, waaQGP, STY1867-68, STY2346, and SPI-4. In particular, 35 new defective phenotypes of Salmonella entry or intracellular survival were revealed in this study. Data generated here provides significant novel insight for elucidating how S. Typhi manipulates its intracellular niche, leading to systemic infection. Genes described represent potential targets for attenuating the bacteria in the human host and could contribute to the development of better vaccine strains to immunize against typhoid fever.

No description available.

No description available.

Os carbapenêmicos são os antimicrobianos mais amplamente utilizados no tratamento empírico de infecções graves por bacilos Gram-negativos. A pressão seletiva gerada pelo uso desses antimicrobianos ao longo das últimas três décadas contribuiu para a disseminação de enterobactérias e Gram-negativos não fermentadores produtores de carbapenemases, particularmente as do tipo KPC e NDM. Os genes que codificam essas enzimas usualmente estão localizados em plasmídeos e/ou transpósons. A hipótese atualmente mais aceita é que o gene blaNDM-1 seja uma quimera criada em Acinetobacter baumannii. A NDM-1 foi descrita em paciente proveniente da Índia e subsequentemente evidenciou-se sua ampla disseminação nesse país. A epidemiologia que tem sido observada nos casos detectados na Europa e Estados Unidos tem sido viagem à Índia, ou seja, sem casos autóctones. No Brasil, os primeiros casos foram identificados no Rio Grande do Sul, e a seguir no Rio de Janeiro e em São Paulo. Diferentemente dos casos da Europa e América do Norte, os casos do Brasil não tem relação epidemiológica com a Índia. O sequenciamento integral dos plasmídeos e cromossomos albergando o gene blaNDM permitirá entender como ocorre a disseminação desse mecanismo de resistência no Brasil. Para isso, foi avaliado o perfil de susceptibilidade dos isolados, bem como a capacidade conjugativa e clonalidade. Das vinte e oito amostras utilizadas neste trabalho, treze delas pertencem à espécie Enterobacter hormaechei, uma à espécie Citrobacter freundii, sete à espécie Escherichia coli, quatro à Klebsiella pneumoniae e três ao gênero Acinetobacter spp. Os primeiros isolados incluídos neste estudo (Escherichia coli e Enterobacter hormaechei produzindo NDM-1) foram isolados em agosto de 2013, de uma mesma amostra de swab retal de um paciente do Rio de Janeiro que nunca viajou para o exterior. O sequenciamento completo do DNA plasmidial utilizando a plataforma Illumina e a anotação de ambos os plasmídeos albergando o gene blaNDM-1 revelou que estes pertencem a grupos de incompatibilidade diferentes, IncFIIK (E. hormaechei) e IncX3 (E. coli), e abrigam um novo transpóson composto designado Tn3000. A comparação da sequência nucleotídica do Tn3000 com aquelas disponíveis no GenBank evidencia que a mesma estrutura está presente em plasmídeos de isolados da cidade de Porto Alegre e também em diferentes continentes. As espécies de Acinetobacter (A. radioresistens, A. ursingii e A. guillouiae) isoladas em São Paulo e Porto Alegre, possuem o gene blaNDM-1 albergados em um mesmo plasmídeo não tipável de 41.087 pb. A avaliação da clonalidade dos isolados de Enterobacter hormaechei \"subsp. oharae\" mostrou dois perfis diferentes através da técnica de PFGE, sendo que todos os microrganismos foram isolados de um surto no mesmo hospital no Rio de Janeiro. Isolados de Klebsiella pneumoniae de uma mesma paciente internada em hospital em Salvador, de sítios distintos - swab retal, hemocultura e urina, em ordem cronológica - obtiveram o mesmo perfil clonal pela técnica de PFGE. O mesmo ocorreu com três isolados de Escherichia coli, de um mesmo paciente do Rio de Janeiro, em amostras de swab retal. Os achados deste estudo evidenciam que no Brasil, Nepal, Marrocos e Índia há uma disseminação do gene blaNDM-1 mediada por um novo elemento móvel designado Tn3000 em enterobactérias. A detecção de um mesmo plasmídeo em diferentes espécies de Acinetobacter evidencia que neste gênero bacteriano, no Brasil, a disseminação do gene blaNDM-1 ocorre por conjugação. / Carbapenems are the antimicrobials most widely used in the empirical treatment of severe infections caused by Gram-negative bacilli. The selective pressure generated by the use of these antibiotics over the last three decades has contributed to the spread of enterobacteria and Gram-negative non-fermenting producing carbapenemases, mainly KPC and NDM. Genes encoding these enzymes are usually located in plasmids and/or transposons. Currently the most accepted hypothesis is that the blaNDM-1 gene is a chimera created in Acinetobacter baumannii. The NDM-1 was described in a patient from India and subsequently was reported to be broadly disseminate in this country. The epidemiology that has been observed in cases detected in Europe and United States is traveling to India, but no autochthonous cases. In Brazil, the first cases were identified in Rio Grande do Sul, and then in Rio de Janeiro and São Paulo. Differently from the cases described in Europe and North America, the cases from Brazil have no epidemiological link with India. The complete sequencing of plasmids and chromosomes harboring blaNDM gene will understanding how the dissemination of this resistance mechanism in Brazil occurs. In this work we will be evaluate the susceptibility profile of the isolates, and their conjugal capacity and clonality. Of the twenty-eight samples used in this study, thirteen of them belong to the species Enterobacter hormaechei, one to Citrobacter freundii, seven to Escherichia coli, four to Klebsiella pneumoniae and three to the genus Acinetobacter sp. The first two isolates included in this study (Escherichia coli and Enterobacter hormaechei) were isolated in August 2013, from the same rectal swab sample from a patient from Rio de Janeiro that never traveled abroad. Complete sequencing of plasmid DNA using Illumina platform and annotation of both plasmids harboring the blaNDM-1 gene revealed that they belong to different incompatibility groups, IncFIIK (E. hormaechei) and IncX3 (E. coli), and are harbor to a new transposon designated Tn3000. The comparison of the Tn3000 nucleotide sequence with those available at GenBank shows that the same structure is present in plasmids from other Porto Alegre and also in different continents. The Acinetobacter species (A. radioresistens, A. ursingii and A. guillouiae) isolated in São Paulo and Porto Alegre, have the blaNDM-1 gene harbored in a single non-typing plasmid of 41,087 bp. The evaluation of clonal relationship of Enterobacter hormaechei \"subsp. oharae\" showed two different profiles by PFGE technique; of note all microorganisms were isolated from an outbreak in the same hospital in Rio de Janeiro. Isolates of Klebsiella pneumoniae from a single patient hospitalized in Salvador, from different anatomical sites - rectal swab, blood culture and urine, in chronological order - obtained the same clonal profile by the PFGE technique. The same occurred with three Escherichia coli isolates, from the same patient from Rio de Janeiro, in swab rectal strains. Our findings suggest that in Brazil, Nepal, Morocco and India there is a spread of blaNDM-1 gene mediated by Tn3000 in enterobacteria. The detection of a same plasmid in different species of Acinetobacter shows that in this bacterial genus, in Brazil, the dissemination of the blaNDM-1 gene occurs by conjugation.