Dissertations / Theses on the topic 'Metallidurans'
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Juhnke, Susanne Doris. "Untersuchungen zur Chromatentgiftung in Ralstonia metallidurans." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972493115.
Full textPribyl, Thomas. "Topologie des CzcCBA-Efflux-Komplexes aus Ralstonia metallidurans CH34." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=961941375.
Full textRossy, Emmanuel. "Prise en charge du mercure inorganique chez Ralstonia metallidurans CH34." Université Joseph Fourier (Grenoble), 2004. http://www.theses.fr/2004GRE10013.
Full textConicelli, Bianca Pirilo. "Biossorção de chumbo e mercúrio pelas linhagens selvagem e recombinante de C. metallidurans em meio aquoso." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-15052017-160603/.
Full textIn the last decades the biosorption process, has achieved great relevance treatment of effluents containing toxic metals. The use of bacteria in the process has several advantages. This study aimed to evaluate the mechanism involved in the biosorption process of Pb (II) and Hg (II) ions by C. metallidurans (CH34) and C. metallidurans (CH34/pCM3) genetically modified strain. The Langmuir isotherm was the best adjusts to the adsorption process. The maximum adsorption capacity (qmax) of 0.98 mg.g-1 for Hg (II) and 86.2 mg.g -1 to Pb (II), for a wild strain (pH 7,0). However, for a recombinant strain, the qmax was 3.4 mg.g-1 for mercury and 172.4 mg.g-1 for the lead (pH 7,0). Based on the Gibbs free energy (ΔG) values on the adsorption process, it occurred chemically and spontaneously. The Hg(II) presented high adsorption capacity at pH=2 in comparing with Pb(II). While Pb(II) presented high adsorption capacity at pH=10. The studies of binding process was robust and stable for 6 months. The results indicate that Cupriavidus metallidurans (CH34/pCM3) can be a good option for biosorption of metal in a bioreactor.
Weltrowski, Annett. "Die Struktur und Funktion des CDF-Proteins CzcD aus Cupriavidus metallidurans." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=984727604.
Full textRoux, Murielle. "Contribution à l'étude de la résistance au sélénite chez Ralstonia metallidurans CH34." Université Joseph Fourier (Grenoble), 2002. http://www.theses.fr/2002GRE10191.
Full textCasares, Proaño Lorena Cecilia. "Identificación y caracterización de la caja SOS de Ralstonia metallidurans y de Deinococcus radiodurans." Doctoral thesis, Universitat Autònoma de Barcelona, 2003. http://hdl.handle.net/10803/3869.
Full textEl propósito de este trabajo ha sido determinar y caracterizar las cajas SOS de dos especies bacterianas, Ralstonia metallidurans y Deinococcus radiodurans, pertenecientes a los grupos b-Proteobacterias y Deinococcus-Thermus, respectivamente.
En primer lugar se realizó la clonación y secuenciación de los genes recA y lexA de R. metallidurans, el primero mediante hibridación con una sonda del gen recA de Agrobacterium tumefaciens y el segundo utilizando programas informáticos en los que se usó la secuencia del gen lexA de E. coli para identificar dicho gen en la secuencia parcial del genoma de R. metallidurans. Tras un análisis de sus regiones promotoras, se determinó que ambas contenían un motivo regulador, CTGT-N8-ACAG, idéntico al de E. coli.
Se comprobó que esta caja reguladora era funcional tanto en R. metallidurans como en E. coli, evaluando su capacidad de inducir el gen recA frente a lesiones en el DNA. Adicionalmente se determinó que la caja SOS de este microorganismo se encontraba en varios genes que, en E. coli forman parte del regulón SOS, como recA, lexA y un hipotético gen de la familia impB/samB/mucB. En cambio, no se identificó dicha caja en los hipotéticos genes uvrA, ruvAB y dinG, los cuales, en E. coli, también integran el regulón SOS. Mediante el análisis cuantitativo por RT-PCR on-line de los tránscritos se demostró que la expresión de todos estos genes era inducible al lesionar el DNA. Asimismo, mediante ensayos de movilidad electroforética, utilizando extractos proteicos de LexA de E. coli purificada y extractos crudos de R. metallidurans y R. metallidurans LexA(Def), se determinó que la proteína LexA era la responsable de la regulación de los genes recA, lexA y el hipotético gen de la familia impB/samB/mucB. Por el contrario, los hipotéticos genes uvrA, ruvAB y dinG no están bajo el control de la proteína LexA. Por lo tanto, si bien R. metallidurans posee una caja SOS idéntica a la de E. coli, solo algunos de los genes integrados en el regulón SOS de E. coli forman parte de este regulón en R. metallidurans. Además, el hecho de que los hipotéticos genes uvrA, ruvAB y dinG sean inducibles por lesiones en el DNA indica que deben estar sometidos a algún control independiente de LexA.
Para determinar la caja SOS de D. radiodurans, se procedió a clonar el gen lexA obteniéndose su secuencia mediante programas informáticos que permiten localizar secuencias de un genoma con un determinado grado de similitud a otras secuencias conocidas. Una vez clonado dicho gen, se sobreexpresó la proteína LexA de este microorganismo y el extracto proteico obtenido se utilizó para realizar ensayos de movilidad electroforética frente al promotor del gen lexA de D. radiodurans, demostrándose que el gen lexA se autorregula. Seguidamente y mediante ensayos de movilidad electroforética se acotó al máximo la región promotora del gen lexA hasta identificar un posible motivo regulador. Mediante mutagénesis dirigida de las diferentes bases de dicho motivo se determinó que la proteína LexA de D. radiodurans reconoce específicamente el palíndromo CTTG-N8-CAAG como motivo de unión, siendo las bases señaladas en negrita las más importantes para la unión proteína-DNA. Finalmente se demostró que otros genes como recA o el hipotético lexA2 no tienen la misma caja SOS ni son regulados por LexA. Se concluye que la proteína LexA de D. radiodurans tiene un motivo regulador diferente a los anteriormente descritos para otros grupos de microorganismos y que debe haber un tipo de regulación diferente a los anteriormente descritos para los genes involucrados en procesos reparativos.
The SOS system in Escherichia coli has been the reference model for its study of other species. This system is present in other microorganisms including gramnegative, grampositive and other bacteria. Lately, some differences have been found between E. coli and other bacterial species in the SOS boxes and genes that compose the SOS regulon.
The purpose of this work is to determine and characterize SOS boxes from two bacterial species, Ralstonia metallidurans and Deinococcus radiodurans, belonging to the b-Proteobacteria and Deinococci group, respectively.
First, recA and lexA genes from R. metallidurans were cloned and sequenced, the former one by a hybridisation using an Agrobacterium tumefaciens recA gene's probe. The latter one was isolated with the help of informatics' programs using E. coli 's lexA gene' s sequence to find this gene in the partial sequenced genome from R. metallidurans. The promoter regions of both genes were analysed and it was discovered that they have the regulating motif, CTG-N8-ACAG, identical with the one of E. coli.
The functionality of this regulating box in R. metallidurans and E. coli was demonstrated by determining the recA gene expression due to damage induction in both species. It was also approved that this SOS box controls the expression of some genes like recA, lexA, and the hypothetical gene of impB/samB/mucB family, which are included in E. coli SOS regulon. In contrast, this SOS box was not identified in other hypothetical genes like uvrA, ruvAB and dinG, which normally belong to E. coli 's SOS regulon. It was demonstrated that all of these genes' expression was induced by DNA damage, using a RT-PCR on-line technique to quantitatively analyse the transcripts. Furthermore, EMSAs (Electrophoretic Mobility Shift Assay), using purified E. coli 's LexA protein and R. metallidurans and R. metallidurans LexA(Def) crude protein extracts, confirmed that the LexA protein was responsible for the regulation of recA, lexA, and the hypothetical gene of impB/samB/mucB family genes. In contrast, hypothetical genes uvrA, ruvAB and dinG are not under the LexA protein control. Therefore, only some genes from E. coli's regulon conform R. metallidurans SOS regulon, even though R. metallidurans has a SOS box identical to E. coli's. Moreover, the fact that hypothetical genes uvrA, ruvAB and dinG are induced by DNA damage indicates that they most likely are under a LexA independent control.
To determine the SOS box from D. radiodurans, the lexA gene was cloned. It's sequence was obtained using informatics programs that allow to locate regions from a genome similar to other known sequences. After cloning the lexA gene, the D. radiodurans 's LexA protein was overexpressed, and the protein extract obtained was used to perform EMSAs with the promoter region from the lexA gene of this microorganism. It was proved that this gene regulates itself. Using the same technique, serial deletions of the lexA promoter region were done, identifying a possible regulating motif. Each of the bases conforming the motif were directly mutagenized and it was determined that the D. radiodurans LexA protein recognizes specifically the palindrome CTTG-N8-CAAG as union motif; the bold printed bases are the most important ones for DNA-protein union. Finally, it was shown that other genes like recA or hypothetical gene lexA2 do not have the same box, and that they are not regulated by the LexA protein. In conclusion, D. radiodurans LexA protein has a regulating motif different from the ones formerly known for other bacterial groups. Most likely, it must be a regulation system which is different from those already defined for genes involved in reparation.
Grass, Gregor B. "Molekulargenetische und biochemische Charakterisierung der cnr Cobalt-Nickel-Resistenz-Determinante aus Ralstonia metallidurans CH34." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=961201673.
Full textMonchy, Sébastien. "Organisation et expression des gènes de résistance aux métaux lourds chez Cupriavidus metallidurans CH34." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210706.
Full textLe génome de cette bactérie contient un chromosome (3.6 Mb), un mégaplasmide (2.6 Mb) et deux plasmides pMOL28 (171 kb) et pMOL30 (234 kb) déjà connus pour porter des gènes de résistance aux métaux lourds.
Nous avons d'abord fait le catalogue des gènes impliqués dans la résistance aux métaux lourds et, ensuite, cherché à mesurer leur expression par deux approches transcriptomiques :RT-PCR et puces à ADN.
L'analyse du génome montre au moins 170 gènes relatifs à la résistance aux ions métalliques localisés sur les 4 réplicons, principalement sur les deux plasmides. Ces gènes codent essentiellement pour des systèmes d'efflux tel que les HME-RND (transport chimioosmotique avec flux de protons à contresens), les ATPases de type P ou encore pour le système de résistance aux ions Cu(II). Dans le génome de C. metallidurans, nous avons identifié 13 opérons qui codent pour des systèmes HME-RND, seuls trois, localisés sur les plasmides, sont surexprimés en présence de métaux lourds. Huit gènes codent pour des ATPases de type P, dont deux appartiennent à une classe dont les substrats ne sont pas métalliques. Deux ATPases appartiennent à une famille spécialisée pour l'efflux du Cu(II) et les quatre autres à une autre grande famille impliquée dans l'efflux des ions Cd(II), Pb(II) et Zn(II). Les analyses transcriptomiques montrent la surexpression des deux premières classes d'ATPases P en présence des métaux lourds. La mutagenèse du gène zntA (mégaplasmide), codant pour l'une des ATPases, provoque une diminution de la viabilité en présence de Zn(II), Cd(II) et dans une moindre mesure de Pb(II), Tl(I) et Bi(III).
Sur pMOL30, la résistance au cuivre implique un groupe de 19 gènes cop codant pour la résistance au cuivre au niveau du périplasme et du cytoplasme, et vraisemblablement pour une forme de stockage du cuivre essentiel. Ces 19 gènes sont surexprimés en présence de cuivre, mais une quinzaine de gènes proches semblent aussi requis pour une expression optimale de la résistance au cuivre.
L'annotation des plasmides a mis en évidence la parenté du plasmide pMOL28 avec le plasmide pHG1 (hydrogénotrophie, fixation du CO2) de C. eutrophus H16 et le plasmide pSym (fixation de l'azote) de C. taiwanensis, et chez pMOL30, la présence de deux îlots génomiques concentrant la plupart des résistances aux métaux lourds. Les puces montrent la surexpression de 83 sur 164 gènes dans pMOL28, et de 143 sur 250 gènes dans pMOL30. Elles montrent aussi que les gènes présents sur les deux plasmides sont davantage surexprimés que ceux localisés sur les deux mégaréplicons. Parmi les gènes surexprimés les plus intéressants du plasmide pMOL30, il faut mentionner des transposases tronquées et des gènes impliqués dans la synthèse des membranes (glycosyltransférases). L'analyse de l'expression des gènes plasmidiens de résistance aux métaux lourds montre la surexpression en présence de plusieurs ions métalliques ajoutés indépendamment et pas seulement par les substrats métalliques de ces opérons, ce qui suggère l'intervention de deux types de régulation dont les gènes correspondants sont aussi localisés sur le chromosome et le mégaplasmide.
Ce travail met en évidence la spécialisation de la bactérie dans la réponse à un grand spectre de concentrations de métaux lourds, jusqu'à la limite majeure de la toxicité observée pour les bactéries mésophiles hétérotrophes. Cette spécialisation correspond bien aux biotopes industriels de divers continents dans lesquels on l'a trouvée.
Doctorat en sciences, Spécialisation biologie moléculaire
info:eu-repo/semantics/nonPublished
Egler, Monique. "Rolle von RpoE-homologen Sigmafaktoren in der Schwermetall-Homöostase von Escherichia coli und Cupriavidus metallidurans." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=980161088.
Full textLegatzki, Antje. "Charakterisierung zweier CPx-Typ ATPasen und deren Zusammenwirken mit anderen Metall-Effluxsystemen in Ralstonia metallidurans." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=970626460.
Full textZiani, Widade. "Interactions des protéines du complexe de transduction du signal transmembranaire CnrYXH chez Cupriavidus metallidurans CH34." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENV059/document.
Full textThe CnrYXH complex contributes to regulate the expression of the regulatory genes and resistance genes involved in cobalt and nickel resistance in Cupriavidus metallidurans CH34. The binding of nickel or cobalt to CnrX in the periplasm induces conformational modifications that could trigger transmembrane signal transduction. As a result, CnrH is made available in cytoplasm for binding to RNA polymerase. The CnrH:RNA polymerase complex binds specifically the cnr promoters and initiates transcription of both the regulatory genes (cnrYXH) and resistance genes (cnrCBAT). In order to delineate the mechanism of signal transduction through the membrane, I studied the interactions between the three partners in the different cellular compartments: periplasm, plasmic membrane and cytoplasm. The identification of the interaction determinants between CnrX, CnrY and CnrH allowed us to propose a structural and functional model for the CnrYXH complex and its homologues. This model brings up new hypothesis on the function of Cnr system
De, Angelis Fabien. "Characterization of proteins involved in RND-driven heavy metal resistance systems of Cupriavidus metallidurans CH34." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210154.
Full textDoctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
Heinz, Anja [Verfasser]. "Die Bedeutung von AtpI für die F1Fo-ATPase in Escherichia coli und Cupriavidus metallidurans / Anja Heinz." Halle, 2017. http://d-nb.info/1142920488/34.
Full textAnton, Andreas. "Genetische und biochemische Charakterisierung von CzcD und anderen Regulatoren der czc-vermittelten Schwermetallresistenz in Ralstonia metallidurans." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=964163357.
Full textWiesemann, Nicole [Verfasser], D. H. [Akademischer Betreuer] Nies, K. [Akademischer Betreuer] Humbeck, and M. [Akademischer Betreuer] Solioz. "Mechanismus der Goldresistenz in Cupriavidus metallidurans / Nicole Wiesemann. Betreuer: D. H. Nies ; K. Humbeck ; M. Solioz." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2015. http://d-nb.info/1080822674/34.
Full textBütof, Lucy [Verfasser]. "Metall-Chaperone in Cupriavidus metallidurans : Charakterisierung der putativen P-loop GTPasen CobW1/2/3 / Lucy Bütof." Halle, 2018. http://d-nb.info/1161729712/34.
Full textCONICELLI, BIANCA P. "Biossorção de chumbo e mercúrio pelas linhagens selvagem e recombinante de C. metallidurans em meio aquoso." reponame:Repositório Institucional do IPEN, 2017. http://repositorio.ipen.br:8080/xmlui/handle/123456789/27961.
Full textMade available in DSpace on 2017-10-27T12:25:12Z (GMT). No. of bitstreams: 0
Nas ultimas décadas o processo de biossorção tem alcançado grande relevância no tratamento de efluentes contendo metais potencialmente tóxicos. O uso de bactérias nesse processo tem obtido destaque, uma vez que possuem inúmeras vantagens. O presente estudo pretendeu avaliar o mecanismo envolvido no processo de biossorção dos íons Pb(II) e Hg(II) por meio das linhagens Cupriavidus metallidurans (CH34) e Cupriavidus metallidurans (CH34/pCM3). Dentre os modelos estudados a isoterma de Langmuir foi a que melhor se ajusta ao processo de adsorção, apresentando uma capacidade máxima de adsorção (qmax) de 0,98 mg.g-1 para o Hg(II) e 86,2 mg.g-1 para o Pb(II), para a linhagem selvagem. Já para a linhagem recombinante o qmax obtido foi 3,4 mg.g-1 para o mercúrio e 172,4mg g-1 para o chumbo. Baseado nos valores referentes à energia livre de Gibbs (ΔG) o processo de retenção ocorreu de forma química e espontânea. A influencia do pH foi avaliada por meio de estudo competitivo entre os íons metálicos, em níveis equimolares. O valor que melhor contemplou a adsorção para ambos os íons foi o pH 7,0, tendo o Pb(II) demonstrado maior capacidade de retenção. Em pH 2,0 houve maior retenção do Hg (II), já em pH 10,0 o Pb(II) obteve maior retenção. Indicando que o meio influencia diretamente na competição dos íons metálicos pelos sítios ativos. Constatou-se que a retenção do metal é robusta e estável ao longo de 6 meses. Os resultados indicam que a Cupriavidus metallidurans (CH34/pCM3) pode ser uma boa opção para biossorção de íons metálicos por meio de biorreator.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
Champier, Ludovic. "Caractérisation des protéines de régulation impliquées dans la résistance au mercure inorganique chez Ralstonia metallidurans CH34." Université Joseph Fourier (Grenoble), 2003. http://www.theses.fr/2003GRE10156.
Full textAlviz, Gazitúa Pablo. "Caracterización de la vía del c-di-GMP en la formación de biopelículas y la resistencia a Cadmio en Cupriavidus metallidurans CH34." Tesis, Universidad de Chile, 2018. http://repositorio.uchile.cl/handle/2250/151337.
Full textEl cadmio es un metal pesado altamente tóxico para los sistemas biológicos. El estudio de microorganismos para la biorremediación de metales pesados, ha destacado a Cupriavidus metallidurans CH34, β-proteobacteria aislada desde instalaciones metalúrgicas, como modelo de resistencia a estos elementos. La biorremediación ex situ de metales pesados es comúnmente llevada a cabo en biorreactores de lecho fijo, donde los metales pesados en solución se concentran en la biomasa de comunidades de microorganismos adheridos a superficies llamadas “biopelículas”. El efecto de los metales pesados sobre la formación de biopelículas en C. metallidurans CH34 no ha sido descrito. Durante las últimas décadas, la vía de señalización mediada por un dinucleótido cíclico llamado “c-di-GMP” ha sido establecida como central en la regulación del estilo de vida bacteriano. La interacción de c-di-GMP con distintos receptores macromoleculares promueve del estilo de vida comunitario. Pese al rol fundamental de las biopelículas en los procesos de biorremediación, el efecto de los metales pesados sobre esta vía de señalización en bacterias ha sido poco estudiado. El objetivo de esta tesis es determinar el efecto del cadmio sobre la vía del c-di- GMP y la formación de biopelículas en C. metallidurans CH34. El cadmio inhibió la formación de biopelículas de C. metallidurans CH34. Esto se correlaciona con la descripción de una baja en los niveles de c-di-GMP tras la exposición a este metal pesado, concomitante con un aumento en la abundancia de un transcrito del gen urf2 de los operones de resistencia a mercurio Tn4378 (urf2.1) y Tn4380 (urf2.2), que codifica una potencial fosfodiesterasa. Ensayos de complementación con el gen urf2.2 de la cepa mutante nula P. aeruginosa PAO1 ΔrocR, carente de la fosfodiesterasa RocR, restituyeron la formación de biopelículas y concentración intracelular de c-di-GMP a niveles de la cepa silvestre. Estos resultados constituyen la primera evidencia de funcionalidad catalítica de la fosfodiesterasa codificada por el gen urf2, por lo que se denominó fosfodiesterasa Mrp (metal regulated phosphodiesterase). De forma coherente con la respuesta inhibitoria de formación de biopelículas mediada por la disminución de los niveles de c-di-GMP en C. metallidurans, niveles elevados de este segundo mensajero generados por una diguanilato ciclasa activa expresada en forma heteróloga, incrementaron la formación de biopelículas y la susceptibilidad a cadmio.
Cadmium is a highly toxic heavy metal for biologic systems. Ex situ heavy metal bioremediation is commonly carried out in fixed bed bioreactors in which heavy metals in solution are removed by adhered microbial communities in biofilms. Cupriavidus metallidurans CH34 is a model strain for heavy metal resistance and bioremediation. However, the effect of heavy metals on C. metallidurans CH34 biofilm formation has not been described. The signaling pathway mediated by the cyclic dinucleotide c-di-GMP is central in bacterial lifestyle regulation. c-di-GMP promotes biofilm lifestyle through the interaction with different receptors. Despite of the central role of biofilms on the bioremediation process, the effect of heavy metals over this signaling pathway has been poorly studied. Thus, the objective of this study was to assess the effect of cadmium on the c-di-GMP pathway and biofilm formation in C. metallidurans CH34. Cadmium exerted an inhibitory effect on C. metallidurans CH34 biofilm formation concomitant with a decrease of c-di-GMP levels. After cadmium exposure an increase in the transcription of the gene urf2 that codes for a phosphodiesterase and is located in the mercury resistance operons Tn4378 (urf2.1) and Tn4380 (urf2.2) was observed. Complementation assays with the urf2.2 gene in Pseudomonas aeruginosa PAO1 ΔrocR mutant null strain that is defective in RocR phosphodiesterase, restored biofilm formation and c-di-GMP intracellular concentration at wild type levels. This is the first evidence of catalytic functionality of the urf2 gene encoded phosphodiesterase, which was named Mrp por metal regulated phosphodiesterase. In agreement with the biofilm formation inhibition mediated by a c-di-GMP drop in C. metallidurans, high levels of this second messenger generated by an active diguanylate cyclase that was heterologously expressed, increased the biofilm formation and cadmium susceptibility of this bacterium.
Trepreau, Juliette. "Perception du stress métallique (nickel/cobalt) par le système de signalisation transmembranaire Cnr chez Cupriavidus metallidurans CH34." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00656119.
Full textAelst, Sébastien van. "Etude fonctionnelle des gènes plasmidiques de résistance au cuivre de Cupriavidus metallidurans: aspects physiologique, biochimique et écologique." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210529.
Full textOn distingue dans l’îlot cop des gènes codant pour des fonctions de résistance proprement dite (essentiellement par détoxication active du cytoplasme et du périplasme). En effet, les mutants de copSRABCD, copF, et dans une moindre mesure copJ et copE deviennent sensibles. Les phénotypes des mutants divergent toutefois suivant que la mutation soit sur un cosmide qui ne porte que l’îlot (pMOL1024) ou dans son plasmide d’origine (pMOL30). Un second groupe de mutants (copVTMK, copG, copL, copQ) se distingue par un phénotype plus résistant ou identique à la souche parente, sauf autour de la CMI. Ces gènes interviendraient donc à la CMI pour assurer la résistance la plus élevée et le maintien d'un état viable latent.
La présence de l’îlot cop permet de contenir le taux d’oxygène radicalaire qui reste à un taux basal lorsque les cellules sont adaptées au cuivre environnent. Après un choc de Cu (ou stress aigu), l’îlot cop répond de façon « explosive » au stress, en consommant l’énergie du potentiel membranaire et en augmentant fortement l’activité de la chaîne respiratoire.
La résistance au cuivre est inductible, mais de façon différenciée pour la souche sauvage (CH34) et celle qui ne porte qu l’îlot cop (AE1744) :la CMI de CH34 triple après adaptation au cuivre, alors que celle d’AE1744 est inchangée. Après un choc de Cu, la résistance au cuivre est plus fortement induite pour AE1744 que pour CH34. Ces observations suggèrent que l’îlot cop ait été sélectionné pour sa capacité à répondre à un stress aigu puis intégré dans un ensemble de gènes plus vaste qui répond à des impératifs de stress chronique.
L’analyse biochimique de CopI, une petite protéine bleue à cuivre, montre qu’elle porte un site analogue à celui des oxydases multicuivre. Son rôle pourrait dès lors être celui d’une réductase multicuivre. La protéine CopK lie de façon très spécifique le Cu(I) et il semble que la liaison du cuivre modifie sa structure. L’analyse écologique a montré que des homologues de copK pourraient être présents dans l’ADN extrait de la terre de biotopes chargés en cuivre, et dans les souches cuprorésistantes qu’on y trouve.
La contribution majeure de cette thèse est de montrer que l’effet d’un stress métallique ne se résume pas à deux états physiologiques « mort ou vif ». Il y a lieu de considérer des états transitoires (choc de Cu, adaptation au métal, survie autour de la CMI, persistance) où interviennent des gènes spécifiques dans un ou plusieurs états donnés. Les résultats biochimiques et physiologiques ne nous éclairent pas encore assez sur les interconversions Cu(I)/Cu(II) ni sur les flux de cations notamment vers l'espace extracellulaire. Cette thèse ouvre des perspectives sur des mécanismes (protection à la CMI, phénotype persistant) assurant la survie des bactéries ou leur potentiel de recolonisation lors d'une diminution de la pression toxique :les gènes copT, copV, copK, copM, copB, copG, copL et copQ semblent impliqués dans ces fonctions.
Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
Avoscan, Laure. "Étude de la résistance de Cupriavidus metallidurans CH34 aux oxyanions sélénite et séléniate : accumulation, localisation et transformation du sélénium." Grenoble 1, 2007. http://www.theses.fr/2007GRE10069.
Full textSelenium is an essential trace element for the living organisms but it is very toxic at high concentration. Selenite and selenate oxides, soluble forms, highly toxic and bio-assimilable, are the most prevalent forms in the environment. Some soil micro-organisms play a dominant role and contribute to the natural cycle of selenium. Our study model, Cupriavidus (formerly Ralstonia) metallidurans CH34, a telluric bacterium characteristic of metal-contaminated biotopes, is known to resist selenite by reducing it into elemental selenium, an insoluble and less toxic form of selenium. In order to better understand the mechanisms of selenium reduction in the bacteria, three methods of speciation were combined (XAS (XANES and EXAFS), HPLC-ICP-MS and SDS-PAGE-PIXE). They were completed by the direct quantification of selenium accumulated in the bacteria. Speciation analyses highlighted the existence of two mechanisms of reduction of selenium oxides in C. Metallidurans CH34. Assimilation transforms selenite and selenate into organic selenium, identified as selenomethionine and leads to its non-specific incorporation into bacterial proteins (presence of selenious proteins). Detoxication precipitates selenite in nanoparticules of elemental selenium. This way of detoxication is not set up after an exposure to selenate although it is nevertheless possible to detect elemental selenium but in very small amount compared to the exposure of selenite. Selenodiglutathion is detected in bacteria stressed by an exposure to selenate in medium limited in sulphate. Bacteria exposed to selenite accumulate 25 times more selenium than when they are exposed to selenate. The study of mutants resistant to selenite, which do not express the membrane protein DedA, showed that the accumulation of selenium after exposure to selenite is decreased compared with the wild strain meaning probable link between the transport of selenite and the DedA protein. Finally, selenate would use the sulphate permease pathway for entering C. Metallidurans CH34
Auquier, Vanessa. "Identification et caractérisation de protéines membranaires impliquées dans les sytèmes de résistance aux métaux lourds chez Cupriavidus metallidurans CH34." Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210785.
Full textSchmidt, Christopher [Verfasser], Dietrich H. [Akademischer Betreuer] Nies, Klaus [Akademischer Betreuer] Hantke, and Robert Gary [Akademischer Betreuer] Sawers. "Die Zur- und ZntR-vermittelte Regulation der Zinktransportsysteme in Cupriavidus metallidurans / Christopher Schmidt ; Dietrich H. Nies, Klaus Hantke, Robert Gary Sawers." Halle, 2016. http://d-nb.info/1122438729/34.
Full textNgonlong, Ekende Elisabeth. "Towards a better understanding of bacterial resistance to heavy metal ions: the case of the Sil and Zne systems from Cupriavidus metallidurans CH34." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209686.
Full textHerzberg, Martin [Verfasser], D. H. [Akademischer Betreuer] Nies, G. [Akademischer Betreuer] Sawers, and W. [Akademischer Betreuer] Maret. "Die Rolle des Zink-Transporters ZupT in der Zinkhomöostase von Cupriavidus metallidurans : [kumulative Dissertation] / Martin Herzberg. Betreuer: D. H. Nies ; G. Sawers ; W. Maret." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2015. http://d-nb.info/1081077662/34.
Full textSendra, Véronique. "Homéostasie et résistance au cuivre chez Cupriavidusmetallidurans CH34 : la proteine CopH et les transporteurs membranaires CuSa et CzcA." Grenoble 1, 2007. http://www.theses.fr/2007GRE10139.
Full textThe copH gene is one of the 19 genes found in the cop c1uster, involved in detoxification of copper from the cytoplasme as weil as from the periplasm, in Cupriavidus meta//idurans CH34, used as a model to study heavy metals resistance in bacteria. The function of CopH protein, located in the periplasm, is not clear yet, but its expression is induced by copper. We analysed the copper binding properties of CopH. The features are consistent with the presence of Cu(II) type 2 centers in a nitrogen ligand field. The only two histidine residus, ligands of copper as we thought, would not interact directly avec Cu(II) ions. The copper site wou Id consist with 45 nitrogen atoms from the backbone of CopH. The study of membrane transporters CusA and CzcA has needed the optimised purification in detergents and the analysis oftheir behaviour in solution
Vidal, Céline. "Etude taxonomique, phylogénétique et génétique des bactéries symbiotes des légumineuses métallicoles adaptées aux sites contaminés par le zinc et le cadmium." Montpellier 2, 2008. http://www.theses.fr/2008MON20232.
Full textAnthyllis vulneraria is a legume present on heavy-metal-enriched spoil heaps of zinc and able to fix nitrogen. It facilitates installation of other vegetal species, allowing fast and lasting post-mining restoration of these sites. Nitrogen-fixing bacteria able to associate with a metallicolous A. Vulneraria ecotype belong to a new species, Mesorhizobium metallidurans. This bacterium is systematically found in all mining samples where metallicolous Anthyllis ecotype is present. To investigate on the origin of this bacterium, a comparative analysis (genetic and phenotypic) of Mesorhizobium associated with metallicolous Anthyllis was performed on contaminated and non contaminated soils. Metallicolous bacteria differ of non metallicolous genetically, taxonomically and in their capacities to tolerate metals. So, M. Metallidurans seems particularly adapted to high level of Zn and Cd. Study of rhizobia associated with several other metallicolous legumes revealed high genetic diversity. It seems that symbiotic bacteria associated with different metallicolous legumes are the result of local adaptations linked to horizontal transfers. Thus, a soil saprophytic bacterium highly adapted to contaminated and able to acquire nodulation genes under selection pressure of plant host would be at the origin of M. Metallidurans
Desaunay, Aurelien. "Etude et modélisation de la biosorption des métaux par les bactéries. Application au transfert du cadmium et du zinc, seuls ou en mélange par Escherichia coli et Cupriavidus metallidurans en colonnes de sable d'Hostun." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00716409.
Full textDesaunay, Aurélien. "Etude et modélisation de la biosorption des métaux par les bactéries. Application au transfert du cadmium et du zinc, seuls ou en mélange par Escherichia coli et Cupriavidus metallidurans en colonnes de sable d'Hostun." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENU049/document.
Full textRecent field observations have demonstrated that supposedly poorly mobile metals can be detected at long distances from their source, highlighting the importance of poorly predicted transport processes. The fast mobilisation of metals by the colloidal and mobile fraction of soils and in particular biotic colloids (bacteria, algae, fungi, virus, etc.), is now identified as an important secondary transport process that can lead, under specific conditions, to accelerated and potentially dominant pollutant transfer towards aquifers. In order to better understand the role of the bacterial compartment of soils to metal leaching, we conducted a coupled study under static and dynamic conditions. Firstly we evaluated Zn and Cd metal biosorption onto active or inactive Gram negative bacteria (Escherichia coli and Cupriavidus metallidurans CH34) by characterizing the sub-cellular distribution of the metals through a cell disruption approach. The quantification of Zn and Cd in extracellular, membrane and cytoplasm compartments of the cells permitted to show that metals are unequally distributed between the three cell compartments and also between the two bacteria. Surprisingly, metals internalization appeared to be the dominant accumulation process of metals (high cytoplasm contents). The physiological state of the cells was also shown to be important in metal management by the bacteria, since metal accumulation in active cells was reduced due to enhanced efflux and/or EPS production mechanisms. These results suggest bacteria can internalize important amounts of heavy metals and also that adsorption onto cell surface is only a first step in metal management by bacteria. The so-determined thermo-dynamic reactivity constants were used to fit metal breakthrough curves performed in natural sand columns. The transport experiments of bacterial cells, metals or mixtures of bacteria and/or metals performed in the second part of the study, demonstrated that bacteria are able to accelerate the in situ mobilization of Cd and Zn retained in natural sand columns. This transport process was shown to be dominant upon aqueous transport and was correctly fitted using a combined transfer and geochemical modelling approach. Altogether, these results showed that, under specific conditions, heavy metal transport by bacterial cells can dominate aqueous transport processes in soils
Juhnke, Susanne Doris [Verfasser]. "Untersuchungen zur Chromatentgiftung in Ralstonia metallidurans / von Susanne Doris Juhnke." 2004. http://d-nb.info/972493115/34.
Full textPribyl, Thomas [Verfasser]. "Topologie des CzcCBA-Efflux-Komplexes aus Ralstonia metallidurans CH34 / von Thomas Pribyl." 2001. http://d-nb.info/961941375/34.
Full textWeltrowski, Annett [Verfasser]. "Die Struktur und Funktion des CDF-Proteins CzcD aus Cupriavidus metallidurans / Annett Weltrowski." 2006. http://d-nb.info/984727604/34.
Full textCHUN, CHIA-YEE, and 莊佳儀. "Structural and Energetic Basis of DNA Specificity by Metalloregulatory Transcription Factor CupR in Cupriavidus metallidurans." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/69927234247404135368.
Full text國立臺灣大學
農業化學研究所
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CupR, the metalloregulatory transcription factor from Cupriavidus metallidurans strain 34, regulates gene expression of metal-resistance operon. When the dimeric CupR coordinates to a metal ion, the metal-CupR complex causes an allosteric underwinding of the DNA at the operator/promoter site, which realigns the -35 and -10 sequences of the promoter. Subsequently, RNA polymerase can contact the promoter sequences leading to transcription activation. So far the detail recognition of CupR with its specific DNA-binding sequences remains unknown. In this research, we study the binding properties of CupR toward specific or non-specific DNA sequences through EMSA (Electrophoretic Mobility Shift Assay), ITC (Isothermal Titration Calorimetry) and CD (Circular Dichroism Spectroscopy). Furthermore, homology modeling and docking methods were used to investigate the recognition modes between CupR and various DNA sequences. Data from EMSA reveals that CupR posesses best binding ability with promoter sequences (PcupA) compared to others. Moreover, chelation of CupR with Au+ ion makes CupR binding to PcupA stronger. Additionally, the ITC thermodynamic parameters of CupR bound to promoter sequences (PcupA) shows a very negative enthalpy and a negative entropy effect which indicating that formation of CupR and PcupA is mainly via hydrogen-bonding. Molecular models of CupR in complexes with various DNAs are analyzed by NucPlot and reveal that three bases may be important for the recognition between CupR and promoter sequence.
Egler, Monique [Verfasser]. "Rolle von RpoE-homologen Sigmafaktoren in der Schwermetall-Homöostase von Escherichia coli und Cupriavidus metallidurans / von Monique Egler." 2005. http://d-nb.info/980161088/34.
Full textLegatzki, Antje [Verfasser]. "Charakterisierung zweier CPx-Typ ATPasen und deren Zusammenwirken mit anderen Metall-Effluxsystemen in Ralstonia metallidurans / von Antje Legatzki." 2003. http://d-nb.info/970626460/34.
Full textGrass, Gregor B. [Verfasser]. "Molekulargenetische und biochemische Charakterisierung der cnr Cobalt-Nickel-Resistenz-Determinante aus Ralstonia metallidurans CH34 / von Gregor B. Grass." 2000. http://d-nb.info/961201673/34.
Full textSendra, Véronique. "Homéostasie et résistance au cuivre chez Cupriavidus metallidurans CH34 : la protéine CopH et les transporteurs membranaires CusA et CzcA." Phd thesis, 2007. http://tel.archives-ouvertes.fr/tel-00180556.
Full textL'étude des transporteurs CusA et CzcA a nécessité une purification optimisée en détergents et l'analyse de leur comportement en solution.
Avoscan, Laure. "Etude de la résistance de Cupriavidus metallidurans CH34 aux oxyanions sélénite et séléniate : accumulation, localisation et transformation du sélénium." Phd thesis, 2007. http://tel.archives-ouvertes.fr/tel-00162019.
Full textAnton, Andreas [Verfasser]. "Genetische und biochemische Charakterisierung von CzcD und anderen Regulatoren der czc-vermittelten Schwermetallresistenz in Ralstonia metallidurans / von Andreas Anton." 2001. http://d-nb.info/964163357/34.
Full textRojas, Molina Nataly Andrea. "Validación de una metodología para la determinación de benceno en suelos mediante HS-GC-FID y su aplicación en biorremediación en suelos co-contaminados con Hg (ii)." Tesis, 2019. http://repositorio.uchile.cl/handle/2250/168732.
Full textLos suelos se han constituido como el principal sumidero de metales pesados y otros contaminantes producto de causas naturales y actividades antropogénicas. Ejemplo de estas actividades son las mineras que liberan metales pesados, tales como Hg+2, Pb+2, Cu+2 y Zn+2, y las plantas petroquímicas que producen hidrocarburos aromáticos como Benceno, Tolueno, Etilbenceno, y Xilenos (BTEX) a partir de la fracción volátil del petróleo. El objetivo de este seminario de título consiste en validar un método analítico para la cuantificación de benceno en microcosmos conformados por muestras de suelo co-contaminado contenidas en viales, a los cuales se le adiciona una bacteria especializada. De esta forma, se desarrolla una metodología para determinar benceno remanente en suelo, carente de solventes orgánicos, simple y costo-efectiva, mediante un sistema de extracción de espacio de cabeza acoplado a un cromatógrafo de gases junto a un detector de ionización de llama (HS-GC-FID), que permita monitorear la cinética de remoción de benceno en un suelo co-contaminado con Hg (II), durante un proceso de biorremediación bacteriana utilizando la cepa modificada genéticamente Cupriavidus metallidurans MSR33 que es altamente resistente a mercurio. De esta manera, en el presente trabajo se utilizó un suelo contaminado con benceno y mercurio como una aproximación a una situación real de co-contaminación, donde se aplicó una técnica de remediación a través de la utilización de bacterias especializadas capaces de remover benceno en presencia de mercurio. La medición de benceno con la metodología validada permitió monitorear la cinética de biorremediación utilizando la bacteria C. metallidurans MSR33 entregando información rápida y veraz al aplicar directamente en viales con microcosmos de suelo contaminados con Benceno 200 mg×Kg-1 y Hg (II) 2 mg×Kg-1. La determinación de benceno permitió demostrar que este proceso de biorremediación conforma una novedosa tecnología costo-efectiva y amigable con el medioambiente, aplicable a suelos impactados con BTEX en presencia de metales tóxicos.
Soils have been established as the main sink for heavy metals and other pollutants due to natural causes and anthropogenic activities. Examples of these are mining activities which release heavy metals, such as Hg+2, Pb+2, Cu+2 and Zn+2, and petrochemical plants which produce aromatic hydrocarbons such as Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) from volatile fractions of petroleum. The aim of this seminar consists of validate an analytical method for the quantification of benzene in microcosms consisting on vials containing co-contaminated soil samples, which are inoculated with a specially adapted bacterial culture. The methodology was developed in order to measure benzene concentrations remaining in soil in an organic solvent-free, simple and cost-effective manner. This was carried by means of a headspace extraction system coupled to a gas chromatograph with flame ionization detector (HS-GC-FID), that allowed to monitor the kinetics of benzene removal in a soil co-contaminated with Hg (II), during the process of bacterial bioremediation with the genetically modified strain Cupriavidus metallidurans MSR33 that is highly resistant to mercury. Thus, soil samples polluted with benzene and mercury were used on this research as a practical approach to a real co-contamination scenario. A remediation technique was applied by means of bacteria specially adapted to remove benzene from soil in presence of mercury. The measurement of benzene with the validated methodology allowed to monitor the kinetics of bioremediation using the C. metallidurans MSR33 bacterial strain delivering fast and accurate information when applied directly in vials with soil microcosms contaminated with Benzene 200 mg×Kg-1 and Hg (II) 2 mg×Kg-1. The determination of benzene allowed to demonstrate that this process of bioremediation forms a novel, cost-effective and environmental-friendly technology, potentially useful for treatment of soils impacted with BTEX in the presence of toxic metals.
Höfle, Caroline. "Untersuchungen zur genetischen Regulation der CO2-Assimilation in Ralstonia spp." Doctoral thesis, 2005. http://hdl.handle.net/11858/00-1735-0000-0006-ABBB-7.
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