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Tome, Lydia [Verfasser]. "Faltung, Assemblierung und Stabilisierung des Transmembranproteins Cytochrom b 6 / Lydia Tome." Mainz : Universitätsbibliothek Mainz, 2015. http://d-nb.info/1064854745/34.
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Krause-Buchholz, Udo. "Translationsaktivatoren der mitochondrialen Cytochrom b-Synthese in Saccaromyces cerevisiae: Membranassoziation, Mutagenese und Protein-Wechselwirkungen von Cbs1p." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2000. http://nbn-resolving.de/urn:nbn:de:swb:14-991052844578-08818.
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Die vorliegende Arbeit beschäftigt sich mit Cbs1p und Cbs2p, zwei spezifische Translationsaktivatoren der COB-mRNA. Im Mittelpunkt standen sowohl die weitere molekularbiologische und biochemische Charakterisierung von Cbs1p als auch ein Screening von Interaktionskandidaten, die mit Cbs1p und/oder Cbs2p physikalisch wechselwirken könnten. Cbs1p liegt als peripheres Membranprotein fest mit der inneren Mitochondrienmembran matrixseitig assoziiert vor. Dabei spielen möglicherweise hydrophobe und/oder Protein-Protein-Wechselwirkungen mit integralen Membranproteinen eine essentielle Rolle bei der Membranverankerung von Cbs1p. Durch die Identifizierug von atmungsdefekten Cbs1p-Mutanten, deren Mutationen in Bereichen mit Homologie zu RNA-bindenden Proteinen liegt, verstärken sich die Hinweise zur Beteiligung von Cbs1p an der direkten physikalischen Wechselwirkung mit dem 5´-leader der COB-mRNA. Darüber hinaus konnte gezeigt werden,, dass die abspaltbare Präsequenz nicht notwendig für einen mitochondrialen Import ist. Die Ergebnisse präzisieren und erweitern das vorliegende Modell der Wirkungsweise der Translationsaktivatoren Cbs1p und Cbs2p (Michaelis, 1991). Aufgrund der Membranverankerung von Cbs1p wird auch die gebundene COB-mRNA in räumlicher Nähe zur Membran gebracht. Darüber hinaus definiert Cbs1p damit möglicherweise auch den Ort der Insertion des nascierenden Apocytochrom b in die Membran. Cbs2p vermittelt die Bindung zur kleinen Untereinheit der mitochondrialen Ribosomen und könnte seinerseits ebenfalls in Interaktionen mit Untereinheiten des bc1-Komplexes involviert sein.
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Hansmann, Tobias [Verfasser], Ulrike [Akademischer Betreuer] Schmidt, and Jana [Akademischer Betreuer] Naue. "Differenzierung von Spezies durch familienspezifische Amplifikation und HRM-Analyse mitochondrialer Genabschnitte (12S rRNA, Cytochrom b)." Freiburg : Universität, 2017. http://d-nb.info/1151446483/34.
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Kranz-Finger, Sarah [Verfasser], Vlada B. [Gutachter] Urlacher, and Karl-Erich [Gutachter] Jaeger. "Oxidation pflanzlicher Triterpenoide mittels Cytochrom-P450-Monooxygenasen / Sarah Kranz-Finger ; Gutachter: Vlada B. Urlacher, Karl-Erich Jaeger." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2019. http://d-nb.info/1196870691/34.
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Kranz-Finger, Sarah Katharina [Verfasser], Vlada B. [Gutachter] Urlacher, and Karl-Erich [Gutachter] Jaeger. "Oxidation pflanzlicher Triterpenoide mittels Cytochrom-P450-Monooxygenasen / Sarah Kranz-Finger ; Gutachter: Vlada B. Urlacher, Karl-Erich Jaeger." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2019. http://d-nb.info/1196870691/34.
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Le-Huu, Priska [Verfasser], Vlada B. [Akademischer Betreuer] Urlacher, and Martina [Akademischer Betreuer] Pohl. "Cytochrom-P450-Biokatalyse: Selektive Oxidation von 14-gliedrigen Makrozyklen und Diterpenoiden / Priska Le-Huu. Gutachter: Vlada B. Urlacher ; Martina Pohl." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2016. http://d-nb.info/1082033871/34.
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Tapalaga, Dan. "NFkB NF-kappa-B, Caspase 3 und Cytochrom-c-Oxidase Licht- und elektronenmikroskopische, immunhistochemische sowie biochemische Untersuchungen am GalN-TNF-[alpha]-Modell der Maus /." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967778077.
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Eltis, Lindsay David. "Interaction of cytochrome b₅ and cytochrome c." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29096.
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The interaction and kinetics of electron transfer between cytochrome b₅ and cytochrome c, two well characterised soluble electron transfer proteins, have been investigated by three techniques. First, fluorescence quenching experiments were done with cytochrome b₅ and porphyrin cytochrome c, a fluorescent analogue of cytochrome c. These quenching studies yielded association constants and structural information for the cytochrome b₅ cytochrome c complex. Second, an analysis of the rate of flavin semiquinone reduction of the cytochromes within the cytochrome b₅ cytochrome c complex yielded information about the structure and electrostatics of die complex. Third, the second order rate constant for ferrocytochrome b₅ reduction of ferricytochrome c was determined under a variety of solution conditions by stopped-flow spectroscopy. Particular effort was directed at evaluating the role of the cytochrome bs heme propionates in the interaction and electron transfer between cytochrome b₅ and c through performing each of diese three studies with a derivative of cytochrome b₅ in which die heme propionates had been esterified (referred to as DME-cytochrome b₅).
The fluorescence quenching studies on the interaction of cytochrome b₅ and porphyrin cytochrome c and die kinetics of flavin semiquinone reduction of the proteins within the cytochrome b₅ cytochrome c complex provided evidence that esterification of the cytochrome b₅ heme propionates, influences the docking geometry of the two proteins. These findings support the predictions of electrostatic calculations [Mauk, M.R., Mauk, A.G., Weber, P.C. & Matthew, J.B. (1986) Biochemistry, 25, 7085] in two respects. First, esterification of the cytochrome b₅ heme propionates detectably increases the separation between die two heme groups in die cytochrome b₅ cytochrome c complex. Second, die cytochrome c heme group is not as sterically hindered in the DME-cytochiome b₅ cytochrome c complex as in die cytochrome b₅ cytochrome c complex.
The stopped-flow studies demonstrate that the bimolecular rate constant for ferrocytochrome b₅ reduction of ferricytochrome c is determined in part by the rate of association of the two proteins. This rate of association is strongly influenced by electrostatic forces. The principal effect of esterification of the cytochrome b₅ heme propionates on the second order rate of electron transfer between cytochromes bs and c is to influence complex formation between these two proteins. The stopped-flow studies further suggest that the reduction potentials of native and DME-cytochromes b₅ are not significantly different when these proteins are bound to cytochrome c.
The nature of electron transfer protein-protein interactions and protein-protein electron transfer is discussed with respect to these findings.Medicine, Faculty of
Biochemistry and Molecular Biology, Department of
Graduate
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Raina, Vikrant. "Part A. Synthesis of Second Generation Dillapiol and Sesamol Analogues; Inhibition of Cytochrom P450 3A4. Part B. Synthesis of Analogs of Z02; Compounds with Potential to Help Regenerate Partially Severed Spinal Cords." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38462.
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Dillapiol is a naturally occurring methylenedioxyphenyl (MDP) compound that acts as an insecticide synergist comparable in activity to the widely used piperonyl butoxide (PBO). More than thirty synthetic analogs of dillapiol and sesamol were prepared and evaluated for their inhibitory activity in a cloned human Cytochrome P450 3A4 (CYP 3A4) enzyme in order to assess their use as pesticide synergists and to determine the next generation of compounds. These compounds represent a second generation of analogs based on the knowledge gained from compounds prepared and evaluated by a former member of our group. The choice of new structures was also influenced by the surprising and important observations by Dr. Suqi Liu that compound 21 inhibited not only CYP 3A4 but also glutathione-S- transferase (GST). A set of compounds related to 21 were sent to BASF (Durham NC) for evaluation of their synergistic activity, toxicity and persistence in soil studies. In a number of instances these analogs outperformed PBO as synergists even when given at 1:1 synergist: pesticide ratio compared to PBO at 5:1 when tested against a variety of resistant insects in BASF laboratories in the USA, Holland, India and Indonesia. All of the compounds
were shown to be non-toxic to animal life. Their half-life in soils was typically less than 10 days. The results obtained form the basis of two BASF - University of Ottawa patent applications. The most potent CYP3A4 inhibitors synthesized as part of this project are the sulfones 15and 15a. These compounds are 107 and 71 times more potent than dillapiol, respectively which has an IC50 of 8.9 ±0.3 µM. The ortho- chlorobenzyl ether 48 was shown to be 74 times more potent than dillapiol. The synthesis of Z02 analogs in which the NH and C (O) substituents of the B unit are in
the ortho-, meta- and para-orientation compared to the meta-orientation of Z02 is reported. The bioactivities of these compounds were compared with previously synthesized meta- substituted analogs to determine which of the three orientations, ortho-, meta-, or para-, resulted in the most potent compounds. In vitro bioassay results obtained by the Brown group allow us to draw conclusions on the effects of the structural characteristics necessary for optimization of activity. Results acquired thus far have suggested that both the ortho- or para- substituted analogs have
reduced activity relative to the meta- substituted analogs. Replacement of the oxygen in the CD unit by a sulfoxide and sulfone gave compounds with slightly improved inhibition of SOX9 but with still lower activity relative to Z02. The SAR performed in this project did not result in compounds superior to Z02. Nevertheless, the results described in this thesis give guidance for future SAR studies. It is recommended that future synthetic efforts be concentrated on the metaoriented analogs.
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Steinebrunner, Iris, Uta Gey, Manuela Andres, Lucila Garcia, and Daniel H. Gonzalez. "Divergent functions of the Arabidopsis mitochondrial SCO proteins: HCC1 is essential for COX activity while HCC2 is involved in the UV-B stress response." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-147367.
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The two related putative cytochrome c oxidase (COX) assembly factors HCC1 and HCC2 from Arabidopsis thaliana are Homologs of the yeast Copper Chaperones Sco1p and Sco2p. The hcc1 null mutation was previously shown to be embryo lethal while the disruption of the HCC2 gene function had no obvious effect on plant development, but increased the expression of stress-responsive genes. Both HCC1 and HCC2 contain a thioredoxin domain, but only HCC1 carries a Cu-binding motif also found in Sco1p and Sco2p. In order to investigate the physiological implications suggested by this difference, various hcc1 and hcc2 mutants were generated and analyzed. The lethality of the hcc1 knockout mutation was rescued by complementation with the HCC1 gene under the control of the embryo-specific promoter ABSCISIC ACID INSENSITIVE 3. However, the complemented seedlings did not grow into mature plants, underscoring the general importance of HCC1 for plant growth. The HCC2 homolog was shown to localize to mitochondria like HCC1, yet the function of HCC2 is evidently different, because two hcc2 knockout lines developed normally and exhibited only mild growth suppression compared with the wild type (WT). However, hcc2 knockouts were more sensitive to UV-B treatment than the WT. Complementation of the hcc2 knockout with HCC2 rescued the UV-B-sensitive phenotype. In agreement with this, exposure of wild-type plants to UV-B led to an increase of HCC2 transcripts. In order to corroborate a function of HCC1 and HCC2 in COX biogenesis, COX activity of hcc1 and hcc2 mutants was compared. While the loss of HCC2 function had no significant effect on COX activity, the disruption of one HCC1 gene copy was enough to suppress respiration by more than half compared with the WT. Therefore, we conclude that HCC1 is essential for COX function, most likely by delivering Cu to the catalytic center. HCC2, on the other hand, seems to be involved directly or indirectly in UV-B-stress responses.
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Malvisi, Lucio. "Functional characterization of cytochrome b₅ reductase and its electron acceptor cytochrome b₅ in Plasmodium falciparum." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003265.
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Lesemann, Silke Sabine [Verfasser], Holger B. [Akademischer Betreuer] Deising, M. Viola [Akademischer Betreuer] Hanke, and Klaus [Akademischer Betreuer] Pillen. "Biodiversität im Wirt-Pathogen-System Apfel-Apfelmehltau (Malus spp., Podosphaera leucotricha (Ell. & Ev.) E. S. Salmon) : Variabilität des Apfelmehltaus auf molekularer Ebene, in der Virulenz auf Malus-Genotypen mit pyramidisierten Resistenzen sowie in Cytochrom-b-bedingter Strobilurinresistenz / Silke Sabine Lesemann. Betreuer: Holger B. Deising ; M.-Viola Hanke ; Klaus Pillen." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2011. http://d-nb.info/1025135482/34.
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Vallières, Cindy. "Agents antimicrobiens ciblant le complexe III de la chaîne respiratoire mitochondriale : caractérisation de nouveaux inhibiteurs et étude du développement des résistances." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00840029.
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Des inhibiteurs du complexe bc1 de la chaîne respiratoire mitochondriale ont été développés comme agents antimicrobiens pour lutter contre des pathogènes de l'Homme et de plantes. Ces drogues ciblent les poches catalytiques Qo et Qi formées par le cytochrome b. La comparaison de séquences de cette protéine montre que les sites Qo et Qi sont bien conservés entre les organismes mais qu'il existe toutefois des variations qui pourraient expliquer leur différence de sensibilité aux drogues. A l'aide du modèle levure S. cerevisiae, nous avons étudié les déterminants de la résistance/sensibilité naturelle à deux antipaludiques se liant au site Qo de Plasmodium: l'atovaquone et RCQ06. Nous avons notamment montré que le résidu 275 joue un rôle clé dans ce phénomène. Une approche similaire est actuellement utilisée pour identifier les facteurs de la sensibilité différentielle à deux drogues ciblant le site Qi des oomycètes. Malheureusement, des cas de résistance acquise à ces antimicrobiens ont été rapportés et ont pour origine des mutations dans le cytochrome b. De ce fait, de nouvelles molécules sont requises pour court-circuiter ces résistances. Au cours de ma thèse, nous avons mis au point un test qui permet de cribler des molécules capables d'inhiber la fonction respiratoire. Nous avons ainsi pu identifier un nouvel inhibiteur du complexe bc1 : D12. Nous avons ensuite déterminé le mode de liaison de cette molécule ainsi que celui d'un composé capable d'inhiber la prolifération de Plasmodium, HDQ, grâce à une collection de mutants des poches catalytiques. HDQ s'est avéré être un inhibiteur du site Qi. Il pourrait être utilisé avec un inhibiteur du site Qo afin de limiter l'apparition de mutations de résistance. D12 est un inhibiteur du site Qo qui est capable notamment de court-circuiter la mutation de résistance à des fongicides du site Qo G143A. Cette dernière a été trouvée chez de nombreux phytopathogènes, mais n'est cependant pas apparue chez des champignons possédant un intron immédiatement après le codon codant pour la glycine 143. En utilisant la levure, nous avons montré que la mutation empêche l'épissage de l'intron en altérant la structure exon/intron. Nous avons également identifié des mécanismes de " by-pass " qui permettent de restaurer la fonction respiratoire du mutant et qui pourraient apparaître chez les pathogènes. Les mutants créés au cours de ma thèse pourront aider à identifier, concevoir et caractériser de nouveaux antimicrobiens et à étudier l'apparition de mutations de résistance.
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Storch, Elizabeth Marie. "Experimental and computational investigations of the stability and dynamics of cytochrome b₅ /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/8155.
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Baer, Kimberly Kay. "Protein Coevolution and Coadaptation in the Vertebrate bc1 Complex." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1994.pdf.
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Morais, Francisco Silverio. "Mutagenesis of cytochrome b-559 in Chlamydomonas reinhardtii." Thesis, Imperial College London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484183.
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Escriou, Mechin Virginie. "Purification de deux cytochromes des granulocytes neutrophiles de lapin : caractérisation et role du cytochrome b558 dans la production des ions superoxyde de la NADPH oxydase : identification et caractérisation d'un nouveau cytochrome b." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10077.
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Quand ils phagocytent des micro-organismes, les neutrophiles actives produisent des quantites importantes d'ions superoxyde, grace a un complexe enzymatique appele nadph oxydase. Le transfert d'un electron, depuis le nadph, jusqu'a l'oxygene moleculaire serait assure par un cytochrome b, le cytochrome b#5#5#8, qui serait un flavocytochrome. Dans le but d'etudier les differents transporteurs d'electrons (heme, fad) qui contribuent a l'activite de production d'ions superoxyde, le cytochrome b#5#5#8 des granulocytes neutrophiles de lapin a ete purifie. Teste en systeme acellulaire, en presence de cytosol, le cytochrome b#5#5#8 purifie par ce protocole est le seul compose membranaire necessaire a la reconstitution d'une activite de production d'ions superoxyde. Des ions superoxyde etant obtenus sans qu'il soit necessaire d'ajouter de la flavine, la presence de flavine endogene sur le cytochrome a ete envisagee. Pourtant, le dosage de fad effectue dans les differentes fractions chromatographiques de la derniere etape de purification du cytochrome b#5#5#8, fait ressortir un pic d'elution du fad decale par rapport au pic d'elution de l'heme. Ces resultats conduisent donc a s'interroger sur le concept de flavocytochrome et sur la validite du systeme acellulaire, pour tester l'activite de production d'ions superoxyde. Au cours de la purification du cytochrome b#5#5#8, une autre hemoproteine (p-30) a ete mise en evidence, purifiee et partiellement caracterisee. Cette hemoproteine presente le meme spectre d'absorption que le cytochrome b#5#5#8. Pourtant, plusieurs de ses caracteristiques, comme le potentiel d'oxydoreduction et la sequence proteique partielle, ont permis de montrer qu'il s'agit d'un nouveau cytochrome b, n'ayant aucune identite de sequence avec le cytochrome b#5#5#8 des phagocytes ou d'autres cytochromes connus. La fonction physiologique de cette hemoproteine dans les neutrophiles n'est pas encore connue. Elle possede pourtant une localisation subcellulaire voisine de celle du cytochrome b#5#5#8, c'est-a-dire a la fois dans la membrane plasmique et dans la fraction granulaire. Apres activation de la cellule, une partie du cytochrome p-30 est transferee dans la membrane plasmique
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Mbarki, Omar. "Etude des contributions enthalpiques et entropiques à la variation d'énergie libre redox de protéines de transfert d'électrons : cytochromes et protéines fer-soufre." Aix-Marseille 1, 1995. http://www.theses.fr/1995AIX11021.
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Dans les systemes biologiques de transfert d'electrons, le potentiel redox d'un type donne de centre varie beaucoup d'une proteine a l'autre. Pour comprendre l'origine de ces variations, nous avons mesure la composante entropique intrinseque ds'#r#c et la composante enthalpique dh' de la variation d'energie libre redox pour une serie de cytochromes de type c et b, et pour des proteines fer-soufre, en utilisant un montage potentiometrique non isotherme. Dans le cas des cytochromes c et b monohemiques, la variation de potentiel de 400 mv qui est observee est due autant a des effets entropiques qu'a des effets enthalpiques. Des experiences a force ionique variable effectuees sur le cytochrome c#5#5#3 de d. Vulgaris hildenborough montrent que la valeur negative de ds'#r#c est due a des effets de solvatation. Ces effets sont attribues aux interactions entre les dipoles du solvant et les propionates de l'heme, une hypothese qui est confirmee par la correlation existant entre l'exposition des propionates au solvant et la valeur de ds'#r#c dans cette serie de cytochromes. Le degre d'exposition des propionates au solvant pourrait egalement moduler la composante enthalpique dh'. Dans le cas des cytochromes tetrahemiques c#3, on observe de grandes variations des parametres thermodynamiques d'un heme a l'autre. Ces variations sont dues aux facteurs mis en evidence chez les cytochromes monohemiques, mais aussi aux interactions redox entre les hemes d'une meme molecule. Les resultats obtenus pour les proteines fer-soufre mettent egalement en evidence l'existence de composantes entropiques importantes. Des experiences a force ionique variable effectuees sur la ferrodoxine 2fe-2s de la cyanobacterie spirulina maxima montrent un comportement complexe dont l'analyse necessite des etudes plus approfondies
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Kollipara, Sireesha. "Theoretical studies of rates of electron transfer between cytochrome b₅ reductase and cytochrome b₅ a thesis presented to the faculty of the Graduate School, Tennessee Technological University /." Click to access online, 2008. http://proquest.umi.com/pqdweb?index=0&did=1674959791&SrchMode=1&sid=2&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1268413954&clientId=28564.
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Lombard, Nicolaas. "The isolation and charcterisation of ovine liver cytochrome b₅." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/19448.
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Dissertation (PhD)--University of Stellenbosch, 2007.ENGLISH ABSTRACT: This dissertation describes how the isolation and characterisation of ovine liver cytochrome b5 was accomplished by referring to the following goals achieved in this study: - The optimisation of the isolation and purification procedure for ovine liver microsomal cytochrome b5 in order to obtain sufficient material for aggregation and immunological studies. - The removal of the membrane binding domain of cytochrome b5 by means of tryptic digestion to establish the role of the carboxyl terminal in ovine cytochrome b5 aggregation. - The raising of antibodies against both the trypsin truncated and intact forms of cytochrome b5 to study the aggregation of the protein. - The investigation into the influence of purified cytochrome b5 on steroidogenesis in ovine adrenal microsomes.
AFRIKAANSE OPSOMMING: Die isolering en karakterisering van skaaplewersitochroom b5, soos beskryf in hierdie proefskrif, is uitgevoer deur die volgende doelwitte suksesvol af te handel: - Die optimalisering van die prosedure vir die suksesvolle isolering en suiwering van skaaplewersitochroom b5 ten einde genoegsame hoeveelhede van die suiwer proteïen te hê vir die bestudering van die aggregasie van die proteïen sowel as ‘n immunologiese studie. - Die verwydering van die membraanbindingsdomein van sitochroom b5 om die invloed van die karboksielterminaal op die aggregering van die proteïen te bestudeer. - Die gebruik van sowel die tripties gesnyde as die intakte vorms van sitochroom b5 om ‘n immuunrespons in hase op te wek vir die verkryging van sitochroom b5 spesifieke anti-liggame. - Die gebruik van die gesuiwerde proteïene om die invloed van sitochroom b5 op adrenale steroïdogenese te bestudeer.
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Kula, Maureen Elizabeth. "The structure and expression of cytochrome b(5) in Drosophila." Case Western Reserve University School of Graduate Studies / OhioLINK, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1058215222.
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Hamilton, Mary Louise Barbara. "Investigating the role of cytochrome b-559 in photosystem II." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415230.
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Paclet, Marie-Hélène. "Le cytochrome b₅₅₈ : cœur membranaire rédox de la NADPH oxydase." Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10018.
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Le cytochrome b₅₅₈ du complexe de la NADPH oxydase génère des ions superoxyde grâce à un transfert d'électrons du NADPH vers l'oxygène. La NADPH oxydase dormante et dissociée dans les cellules au repos dépend pour fonctionner de l'assemblage de protéines cytosoliques (p47-phox, p67-phox, p40-phox et Rac) sur le constituant membranaire redox, le flavocytochrome b₅₅₈, hétérodimère forme de deux sous-unités gp91-phox glycosylée et p22-phox. Actuellement, les modalités de transfert des électrons au niveau du cytochrome b₅₅₈ ainsi que les mécanismes d'assemblage des facteurs cytosoliques restent méconnus. Pour aborder ces aspects nous avons utilisé deux modèles : le lymphocyte B-EBV : qui exprime tous les composants de la NADPH oxydase mais dont l'activité oxydase est réduite, et le neutrophile qui sert de référence. 1) le cytochrome b₅₅₈ a été isole et purifie à partir des membranes de LB-EBV. Il est le facteur limitant l'activité oxydase dans ces cellules lorsqu'il est inséré dans les membranes, mais une fois purifie, ses propriétés biochimiques sont semblables à celles du neutrophile 2) sa forte glycosylation dans les LB-EBV n'influence pas l'activité oxydase 3) l'étude des mécanismes d'assemblage des protéines du complexe a été réalisée par deux approches : la reconstitution d'une activité oxydase en milieu acellulaire mettant en contact le cytochrome b₅₅₈ purifie et les facteurs cytosoliques recombinants, et l'étude par microscopie a force atomique de la topographie de liposomes contenant le cytochrome b₅₅₈ après assemblage de la NADPH oxydase. Les résultats montrent une augmentation de la taille des liposomes après assemblage des facteurs cytosoliques suggérant que in vitro, la transition de l'état inactif vers l'état actif pourrait faire intervenir un processus de régulation conformationnelle dans lequel p67-phox jouerait un rôle central. Ce travail se poursuit avec un nouveau modèle, dictyostelium discoideum chez qui nous avons caractérisé une activité NADPH oxydase.
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Tron, Thierry. "L' ubiquinol-cytochrome C réductase de Saccharomyces cerevisiae : étude des relations structure-fonction pour la cytochrome B." Aix-Marseille 2, 1991. http://www.theses.fr/1991AIX22037.
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Les complexes respiratoires de type bc sont des enzymes transducteurs d'energie communs a tous les eucaryotes et a de nombreuses especes procaryotes. Dans ce complexes, le cytochrome b joue un role central dans le transfert des electrons et dans la translocation des protons a travers la membrane. Plusieurs mutants, affectes dans le gene du cytochrome b, ont ete utilises pour etudier les relations structure-fonction de cette proteine membranaire. Cette etude porte plus particulierement sur une region de cytochrome b susceptible de former une partie du centre d'oxydation de l'ubiquinol (qo). Nos resultats montrent que la region du cytochrome b comprise entre les acides amines 126 et 147, fait partie des domaines d'interaction du cytochrome b avec, d'une part l'ubiquinol, d'autre part chacun des deux inhibiteurs myxothiazole et stigmatelline; ces domaines sont probablement chevauchant. De plus, il semble que dans cette region l'aa 137 interfere directement ou indirectement, avec la capacite de croissance aerobie des cellules. L'interpretation de ces resultats et de l'ensemble des donnees disponibles dans la litterature, nous a conduit a proposer un modele de structure du cytochrome b dans la membrane
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Sezonlin, Michel. "Phylogéographie et génétique des populations du foreur de tiges de céréales Busseola fusca (Fuller) (Lepidoptera, Noctuidae) en Afrique subsaharienne : implications pour la lutte biologique contre cet insecte." Paris 11, 2006. http://www.theses.fr/2006PA112195.
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Busseola fusca (Fuller) (Lepidoptera, Noctuidae) est un ravageur majeur du maïs et du sorgho cultivé en Afrique Subsaharienne. Des différences observées dans les traits de vie et l'écologie de l'espèce entre les populations Est et Ouest africaines suggèrent l'existence de populations génétiquement différenciées selon la géographie ou les types de biotopes. Le rôle des plantes hôtes, et notamment celui des deux principales plantes cultivées consommées par l'insecte, dans l'éventuelle structuration génétique de ses populations est à déterminer. Une vaste étude phylogéographique basée sur l'utilisation d'un marqueur mitochondrial, le cytochrome b et sur l'analyse de nombreux échantillons (590 individus provenant de 112 localités incluant la majeure partie de l'aire de distribution de foreur), a été réalisée. Cette étude a révélé l'existence de trois clades principaux d'haplotypes (W, KI, KII) correspondant à des populations isolées à l'Ouest et à l'Est de l'Afrique au Pléistocène, il y a environ un million d'années. Le clade W localisé en Afrique de l'Ouest est isolé géographiquement des clades KI et KII qui sont partiellement sympatriques. Le clade KI voit sa distribution limitée à une partie de l'Afrique de l'Est alors que le clade KII présente une large distribution géographique couvrant l'Est, le Centre et le Sud de l'Afrique Subsaharienne. Les résultats des analyses phylogénétiques, les paramètres démographiques calculés, les statistiques de Wright ainsi que les analyses des clades emboîtés confirment que ces trois populations, après avoir été isolées dans des aires refuges différentes, ont connu une expansion démographique et géographique, même si les populations locales sont caractérisées par des phénomènes de restriction des flux géniques avec isolement par la distance. L'analyse de mismatch distribution et les valeurs négative de l'indice D de Tajima sont en accord avec l'hypothèse d'une expansion démographique des trois clades. Des différenciations génétiques significatives ont été mises en évidence à différents niveaux hiérarchiques par l'analyse moléculaire de la variance (AMOVA). La Ligne Volcanique du Cameroun et la Rift Valley seraient deux des facteurs qui ont modelé la structure génétique des populations de B. Fusca. La plus grande diversité haplotypique et nucléotidique de B. Fusca dans les régions ghanéenne (clade W), érythréenne (clade KI) et kenyane (clade KII) a permis de les identifier comme les centres probables d'origine géographique de chaque clade. L'histoire génétique des populations de B. Fusca, telle que révélée par l'analyse du génome mitochondrial, apparaît indépendante de la domestication du sorgho et de l'introduction et de l'expansion des cultures de maïs. L'ancienne structure génétique est maintenue à travers les différentes époques avec un passage récurrent et local des individus de B. Fusca des plantes hôtes sauvages aux cultivées. Un parallèle original a pu être fait entre les résultats de l'étude phylogéographique de cet insecte graminivore et ceux de plusieurs études portant sur des mammifères herbivores africains. Cette analyse parallèle montre que des facteurs paléo-climatiques similaires ont probablement modelé les populations des animaux de groupes éloignés associés aux milieux graminéens africainsBusseola fusca (Fuller) (Lepidoptera, Noctuidae) is a major pest of maize and cultivated sorghum in sub-Saharan Africa. The observed difference in the life features and the ecology of species among East and West African populations suggest the existence of populations genetically differentiated in accordance with the geography or biotope types. The role of host plant, particularly that related to two major cultivated plant consumed by insect, in possible of genetic structure of its populations is being established. A large phylogeographic study based on use of one mitochondrial marker, the cytochrome b and on analysis of numerous samplings (590 individuals from 112 localities including the major part of the spatial distribution of borer) has been performed. This study has showed the presence of three main haplotype clades (W, KI, KII) corresponding to populations isolated in West and East Africa in Pleistocene, around one million years ago. Clade W localized in West Africa split geographically from clade KI and clade KII that are partially sympatric. Clade KI is limited to one part of East Africa whereas clade KII shows a large geographical distribution covering well East, Central and Southern sub-Saharan Africa. Phylogenetic, F-statistics, calculated demographic parameters and nested clade phylogeographic analyses results confirmed that the clades, after their isolation in three different refuge areas, experienced geographic and demographic expansion even if local populations were characterized by the phenomena of restricted gene flow with isolation by distance. Mismatch distribution analysis and the negative values of Tajima D index are consistent with a demographic expansion hypothesis of three clades. Significant genetic differentiations have been highlighted at various hierarchical levels by analysis of molecular variance (AMOVA). The Cameroon Volcanic Line and the Rift Valley appear to be two factors contributing to the genetic structure of B. Fusca populations. The highest haplotype and nucleotide diversity in Ghanaian (clade W), Eritrean (clade KI) and Kenyan (clade KII) regions has allowed identifying them as the likelihood geographic centres of origin of each clade. The population genetic history of B. Fusca as revealed by mitochondrial genome analysis appears independent to sorghum domestication and introduction and expansion of maize. The ancient genetic structure is maintained through different periods with recurrent and local shift of B. Fusca individuals from wild host plants to cultivated. An original parallel has been able to be performed with the results of phylogeographic study of this graminaceous insect and all those of many studies related on African mammalian herbivorous. This parallel analysis indicates that similar paleoclimatic factors have likely shaped animal populations from distant groups associated with African graminaceous environments
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Funk, Walter David. "Expression and characterization of two recombinant mammalian metalloproteins : |b bovine microsomal cytochrome b₅ and human serum transferrin (N lobe)." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30835.
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Two separate systems were developed for the expression of recombinant metalloproteins. A synthetic gene encoding the lipase-solubilized form of bovine liver microsomal cytochrome b₅ was designed and assembled for expression in E. coli. Analysis of the initial recombinant cytochrome revealed differences in several physical characteristics of the molecule compared to the authentic bovine liver species, including a reduction potential that was lower by 17 mV. Further studies showed the primary sequence of the initial recombinant differed from the authentic protein in the amidation status of three residues which, when corrected yielded a recombinant protein identical in behaviour to the authentic protein.
The participation of Ser64 in the stabilization of the oxidized form of cytochrome b₅ was investigated using site-directed mutagenesis to alter this residue to Ala, which was predicted to ablate a hydrogen bond formed between the protein and heme-propionate 7. Spectroelectrochemical analysis of this variant showed that the reduction potential had been shifted downwards by 7 mV, in contrast to predictions from a structural model describing the red/ox behaviour of cytochrome b₅ (Argos and Mathews, 1975). The role of heme carboxylates in determining the reduction potential was confirmed for both the wild-type and Ala64 variants by heme replacement studies using the esterified derivative of protoporphyrin IX, suggesting that the presence of free carboxylates contributes to the stabilization of the oxidized species. In addition, constructions for the expression of the trypsin-solubilized form of bovine liver microsomal cytochrome b₅ and the erythrocytic form of human cytochrome b₅ are described.
A tissue culture cell system was developed for the expression of the N-terminal half molecule of human serum transferrin. The recombinant molecule (hTF/2N) was secreted at high levels from selected eukaryotic cells, and displayed high identity with
the proteolytically-derived molecule from authentic human serum transferrin as judged by sequence analysis, electrophoretic mobility and iron binding capacity. A construction for the expression of the C-terminal half molecule was assembled but failed to express recombinant protein when introduced into tissue culture cells.
The production of these two heterologous expression systems allows for high-level recovery of recombinant protein and provides a convenient approach to structure-function studies employing site-directed mutagenesis techniques.Medicine, Faculty of
Biochemistry and Molecular Biology, Department of
Graduate
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Gardim, Sueli [UNESP]. "Relação filogenètica entre sete espécies de Triatominae (Hemiptera, Reduviidae) da região Centro-Oeste do Brasil baseada no sequenciamento de genes mitocondriais." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/95826.
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gardim_s_me_arafcf.pdf: 1853681 bytes, checksum: 3bd67f0a8ef8c760824f1c5ffaea5e3e (MD5)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Universidade Estadual Paulista (UNESP)
A doença de Chagas tem como agente etiológico o protozoário Trypanosoma cruzi, cujos vetores pertencem à subfamília Triatominae. Os triatomíneos distribuem-se distribuídos por toda região Neotropical e epidemiologicamente se destacam as espécies dos gêneros Panstrongylus, Rhodnius e Triatoma. O gênero Triatoma é o mais numeroso e foi subdividido em complexos específicos de acordo com semelhanças morfológicas e distribuição geográfica de suas espécies. As sete espécies estudadas podem ser encontradas na região Centro-Oeste do Brasil, das quais seis pertencem ao subcomplexo matogrossensis (T. baratai, T. costalimai, T. guazu, T. matogrossensis, T. vandae e T. williami). A outra espécie, T. sordida pertence ao subcomplexo sordida. O objetivo deste estudo foi determinar a posição filogenética das sete espécies ocorrentes na região Centro-Oeste, por meio de comparação das sequências dos fragmentos citocromo b e 16S do DNA mitocondrial, visto que até o momento não foi determinada a posição de T. baratai e T. vandae com base em dados moleculares. Os exemplares avaliados são oriundos de colônias mantidas junto ao Insetário de Triatominae da Faculdade de Ciências Farmacêuticas/UNESP - Araraquara. Após a extração do DNA genômico e da amplificação dos fragmentos 16S e Cytb, procedeu-se o sequenciamento do DNA em sqüenciador automático, modelo ABI 377. As sequências obtidas juntamente com outras sequências (do mesmo fragmento) já disponíveis no GenBank, foram alinhadas com auxílio do programa Clustal W do BioEdit e as inferências filogenéticas foram conduzidas utilizando-se análises de parcimônia e de distância com o programa MEGA 3.1. De acordo com os resultados encontrados, T. costalimai mostrou-se mais distante das demais espécies e foi posicionada como grupo externo. As outras espécies distribuíram-se em dois grupos:..
The protozoan Trypanosoma cruzi, the etiologic agent of Chagas' disease, is transmitted by vectors that belong to the subfamily Triatominae. The triatomines are distributed throughout the Neotropical region and species from Panstrongylus, Rhodnius and Triatoma genus stand out epidemiologically. The Triatoma genus is the largest and was divided in specific complexes according to morphological similarities and geographical distribution of its species. The seven species studied can be found in the Central West Region of Brazil, of which six belong to the matogrossensis subcomplex (T. baratai, T. costalimai, T. guazu, T. jurbergi, T. matogrossensis, T. vandae and T. williami). The other specie, T. sordida belong sordida subcomplex. The aim of this study was to determine the phylogenetic position of the seven species from Central West Region by comparing the 16S and Cytb fragments sequences of the mitochondrial DNA, since so far not been given the position of T. baratai and T. vandae based DNA sequences. The specimens evaluated came from colonies maintained at the Insectarium of Triatominae, Faculdade de Ciências Farmacêuticas / UNESP - Araraquara. After extraction of genomic DNA and amplification of the 16S and Cytb fragments, it was sequenced in an automatic DNA sequencer, model ABI 377. The sequences obtained and other sequences (of the same fragment) already available in GenBank were aligned using the Clustal W program of BioEdit and the phylogenetic inferences were conducted using the analysis of parsimony and distance with the MEGA 3.1 program. According to the results, T. costalimai was more distant from other species and was placed as an outside group. Other species are distributed in two groups, the first comprising the species T. vandae very close to T. matogrossensis and external of these, T. sordida. The second group includes T. guazu strongly related to T. williami... (Complete abstract click electronic access below)
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Rocha, Cláudia Solano [UNESP]. "Variabilidade genética de três colônias de Triatoma rubrovaria (Blanchard, 1843), (Hemiptera, Reduviidae), oriundas do estado do Rio Grande do Sul, avaliadas por meio do seqüenciamento de genes do DNA mitocondrial e ribossomal." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/95828.
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rocha_cs_me_arafcf.pdf: 697628 bytes, checksum: 703b47e347bee1b853ea18538df8a3e2 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Atualmente são admitidas 143 espécies da subfamília Triatominae que estão agrupadas em 18 gêneros e seis tribos. Essa classificação baseia-se principalmente em características morfológicas. Dentre essas espécies temos Triatoma rubrovaria, que pode ser encontrado no Estado do Rio Grande do Sul (Brasil), Uruguai e em algumas regiões da Argentina. Algumas espécies de Triatominae apresentam coloração e características morfológicas semelhantes, o que dificulta a identificação dos exemplares. Ferramentas como a morfometria, citogenética, retrocruzamentos e técnicas de biologia molecular são metodologias importantes para a identificação dessa subfamília. Estudos morfométricos prévios realizados com três populações de T. rubrovaria mantidas no Insetário de Triatomíneos do Laboratório de Parasitologia da Faculdade de Ciências Farmacêuticas revelaram a existência de diferenças morfométricas estatisticamente significativas entre a colônia de Caçapava do Sul (CS) e as duas colônias de Quaraí (QI e QII). Diferenças no padrão de cor do pronoto entre as três populações também foram observadas. A fim de avaliar a variabilidade genética dessas populações, analisaram-se as seqüências nucleotídicas do Citocromo B (Cyt B) e 16S, pertencentes ao DNA mitocondrial e o 28S, ao DNA nuclear. Dentre os marcadores utilizados, o Cyt B apresentou maior variabilidade, seguido do 28S e 16S, respectivamente. Devido ao seu maior polimorfismo o Cyt B mostrou-se um marcador eficaz para estudos de variabilidades...
Currently 143 species of the subfamily Triatominae, grouped into 16 genera and 6 tribes are recognized. This classification is mainly based on morphological characteristics. These species include Triatoma rubrovaria, which can be found in the state of Rio Grande do Sul (Brazil), Uruguay and some regions of Argentina. Some species of Triatominae have similar color and morphological characteristics, which complicates the identification of specimens. Morphometry, cytogenetics, backcrossing and molecular biology techniques are important methods for the identification of this subfamily. Previous morphometric studies carried out on three populations of T. rubrovaria maintained in the Insetário de Triatomíneos do Laboratório de Parasitologia of the Faculdade de Ciências Farmacêuticas have revealed the existence of statistically significant morphometric differences among the colony from Caçapava do Sul (CS) and the two colonies from Quaraí (QI and QII). Differences were also observed in the color patterns of the pronotum among the three populations. The sequences of Cytochrome B (Cyt B) and 16S, belonging to the mitochondrial DNA and 28S, the nuclear DNA, were analyzed to assess the genetic variety of these populations . The Cyt B showed the greatest variability, followed by 28S and 16S. It was concluded that Cyt B is the best marker for effective studies of population variability by virtue of its grater polymorphis ...(Complete abstract click electronic access below)
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Lesemann, Silke Sabine [Verfasser], Dr Deising Holger B. [Akademischer Betreuer] Prof, Dr Hanke Magda-Viola [Akademischer Betreuer] Prof, and Dr Pillen Klaus [Akademischer Betreuer] Prof. "Biodiversität im Wirt-Pathogen-System Apfel/ Apfelmehltau (Malus spp./ Podosphaera leucotricha (Ell. & Ev.) E.S. Salmon): Variabilität des Apfelmehltaus auf molekularer Ebene, in der Virulenz auf Malus-Genotypen mit pyramidisierten Resistenzen sowie in Cytochrom b-bedingter Strobilurinresistenz / Silke Sabine Lesemann. Julius Kühn-Institut. Martin‐Luther‐Universität Halle‐Wittenberg, Institut für Agrar- und Ernährungswissenschaften, Naturwissenschftliche Fakultät III. Gutachter: Holger B. Prof. Dr. Deising ; Magda-Viola Prof. Dr. Hanke ; Klaus Prof. Dr. Pillen." Quedlinburg : Julius Kühn-Institut, 2011. http://d-nb.info/110556942X/34.
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Hope, Elizabeth Lee. "The NADPH oxidase in human neutrophil cell-free systems." Thesis, University of the West of England, Bristol, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389996.
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Furtner, Genevieve. "Phylogeography of Highlands walleye in eastern North America." Ohio University Honors Tutorial College / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1429887556.
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LeDuc, Richard Gene. "A systematic study of the Delphinidae (Mammalia: Cetacea) using cytochrome B sequences /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9823708.
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Salou, Gabrielle. "Le Cytochrome b et l'organisation moléculaire du complexe III répercussions de mutations exoniques faux-sens dans le gène du cytochrome b sur le complexe III mitochondrial de Saccharomyces cerevisiae /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376096753.
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Salou, Gabrielle. "Le cytochrome b et l'organisation moléculaire du complexe III : répercussions de mutations exoniques faux-sens dans le gène du cytochrome b sur le complexe III mitochondrial de Saccharomyces cerevisiae." Aix-Marseille 1, 1987. http://www.theses.fr/1987AIX11078.
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Le complexe mitochondrial a ete isole a partir d'une souche sauvage de saccharomyces cerevisiae et de deux mutants v384 et m4110, porteurs d'une mutation faux sens dans le gene de structure au cytochrome b. Le mutant v384 a conserve une forte affinite pour l'antimycine tandis que m4110 ne fixe pas l'antibiotique. Les etudes biochimiques et spectrales de deux groupes de mutants faux sens, dont l'un a conserve la capacite de transferer des electrons dans le segment bc::(1) de la chaine respiratoire et l'autre pas, ont permis de mettre en evidence une voie de transfert d'electrons secondaire venant du nadh et passant directement par le cytochrome c. Cette voie est insensible aux inhibiteurs (antimycine, cyanure acide cylhydroxamique), elle fonctionne seule dans les mutants du second groupe et existe a l'etat latent dans les autres souches
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Wood, Rebekah. "Lipid Raft TNF-a Pathway Analysis of Cytochrome C with Methylparaben and UV-B Treatment." Marietta College Honors Theses / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=marhonors1430066140.
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Farrow, Neil Richards Jack Richards Jack. "Investigation of electron transfer in the [alpha]-helical protein cytochrome b [subscript 562] /." Diss., Pasadena, Calif. : California Institute of Technology, 1999. http://resolver.caltech.edu/CaltechETD:etd-02082007-151616.
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Thesis (Ph. D.)--PQ# 3203855.Chemistry copy has 284 leaves with a different font and a few blank pages; also in the figures there is a 4-13 and a 413 making a total of 24 in chapter 4. The red copy has the correct numbering, so has 25 figures in chapter 4. The content is the same in both. Includes bibliographical references.
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Fox, Cheryl-Leigh. "An investigation into the catalytic activity of porcine cytochrome P450 17α-hydroxylase/17,20-lyase." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86634.
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Thesis (MSc) Stellenbosch University, 2014ENGLISH ABSTRACT: In this study, the effect of the amino acid residues at positions 40 and 407 on the catalytic activity of porcine CYP17A1 was investigated. Porcine cofactor CYB5 was cloned from porcine liver tissue and its effect on the catalytic activity of porcine CYP17A1 was determined. The influence of rat, human and angora CYB5 on the lyase activity of porcine CYP17A1 was subsequently determined and compared to the influence of porcine CYB5. Wt porcine CYP17A1, which has residues Val40 and His407, catalysed the conversion of prog efficiently with ~50% prog converted to 17OHprog (~40%) and A4 (~10%) after 3 hr. After 24 hr, negligible levels prog remained with ~71% 17OHprog and ~25% A4 being produced. Low levels of 16OHprog were formed (~9%). The Leu105Ala mutation reduced wt 17α-hydroxylase activity, with 70% prog remaining after 24 hr while 16OHprog (~10%) levels remained unchanged. Porcine CYP17A1 with residues Leu40 and His407, exhibited similar catalytic activity towards prog as did wt porcine CYP17A1 (Val40 and His407 residues), while porcine CYP17A1 with residues Leu40 and Leu407 increased the formation of A4 2-fold to 54% at 24 hr and porcine CYP17A1 with residues Val40 and Leu407 resulted in the highest formation of A4 (90%). Wt porcine CYP17A1, while having converted 95% of the prog substrate, produces only ~16% A4 after 24 hr. In the presence of porcine CYB5, however, the lyase activity was stimulated with 85% of prog being converted to A4 and only 13% 17OHprog remaining. The lyase activity was also stimulated by CYB5 from other species, resulting in an increase in A4 production of 60.6%, 24% and 11.6% by rat, angora and human CYB5, respectively. The degree of lyase stimulation correlated to the percentage identity of the CYB5 amino acid sequences to porcine CYB5. While the Val and Leu residues at position 40 do not appear to influence the lyase activity of porcine CYP17A1 as prominently as the residue at position 407, it is the charged residue at 407 that plays a significant role in the production of A4, decreasing A4 production irrespective of the Val and the Leu residues at position 40. It would, furthermore, appear that the stimulation of lyase activity of CYP17A1 is the greatest when assaying this activity in the presence of CYB5 of the same species as was detected when co-expressing porcine CYP17A1 and porcine CYB5.
AFRIKAANSE OPSOMMING: In hierdie studie is die invloed van die aminosuurresidue by posisies 40 en 407 op die katalitiese aktiwiteit van vark CYP17A1 ondersoek. Vark CYB5 is geklooneer vanuit vark lewer weefsel en die effek van hierdie kofaktor op die katalitiese aktiwiteit van vark CYP17A1 is bepaal. Die invloed van rot, mens en angora CYB5 op die liase aktiwiteit van vark CYP17A1 is daarna bepaal en vergelyk met die invloed van vark CYB5. Vark CYP17A1-VH, (kodeer Val40 en His407), kataliseer die omskakeling van prog doeltreffend met ~50 % prog wat omgeskakel word na 17OHprog (~40%) en A4 (~10%) na 3 uur. Na 24 uur, is feitlik alle prog omgeskakel, met ~71% 17OHprog en ~25% A4 geproduseer. Lae vlakke 16OHprog is ook gevorm (~9%). Die Leu105Ala mutasie verminder 17α- hidroksilase aktiwiteit, met 70% prog wat na 24 uur nie omgesit is nie, terwyl 16OHprog (~10%) vlakke onveranderd gebly het. Vark CYP17A1-LH (kodeer Leu40 en His407), en CYP17A1-VH het diselfde katalitiese aktiwiteit teenoor prog getoon, terwyl vark CYP17A1-LL (kodeer Leu40 en Leu407) die vorming van A4 2-voudig verhoog het tot 54% na 24 uur. Vark CYP17A1-VL (kodeer Val40 en Leu407) se katalitiese aktiwiteit het gelei tot die hoogste vorming van A4 (90%). Alhoewel CYP17A1-VH, 95% van die prog substraat omgeskakel het is slegs ~16% A4 geproduseer na 24 uur. In die teenwoordigheid van vark CYB5 is die liase aktiwiteit egter gestimuleer, en is 85% van die prog substraat omgeskakel na A4 met slegs 13% 17OHprog teenwoordig na 24 uur. Die liase aktiwiteit is ook gestimuleer deur CYB5 van ander spesies, wat lei tot 'n toename in A4 produksie van 60,6% , 24% en 11,6% deur rot, angora en menslike CYB5, onderskeidelik. Daar is gevind dat daar’n sterk korrelasie is tussen die stimulering van die liase aktiwitieit en die persentasie aminosuur volgorde identiteit van CYB5 afkomstig vanaf die verskillende spesies. Terwyl die Val en die Leu aminosuurresidu op posisie 40 wel die liase aktiwitiet tot ‘n mate beȉnvloed, blyk dit uit die data dat die potitief gelaaide residue by 407 'n belangrike rol speel in die produksie van A4, en A4 produksie verlaag ongeag van die Val en die Leu residu by posisie 40. Dit wil ook verdermeer voorkom asof die stimulering van die liase aktiwiteit van CYP17A1 die hoogste is wanneer die ensiem gekataliseerde reaksie deurgevoer word in die teenwoordigheid van CYB5 en CYP17A1 afkomstig vanaf dieselfde spesies.
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Dumas, Louis. "Regulatory roles of the cytochrome b6f complex in redox sensing and state transitions in Chlamydomonas reinhardtii : a structure-function study." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0026/document.
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Pour optimiser l’efficacité photosynthétique, les organismes de la lignée verte régulent la distribution de l’excitation lumineuse entre les deux photosystèmes grâce aux transitions d’état. Par un mécanisme encore inconnu, le cytochrome (cyt) b6f détecte ces changements redox et transmet un signal d’activation à la kinase des transitions d’état, Stt7. Afin de comprendre le rôle du cyt b6f, nous avons mis au point une stratégie expérimentale combinant la mutagénèse aléatoire d’un gène chloroplastique par PCR error-prone, la transformation chloroplastique et la sélection des clones sur leur croissance phototrophe. Les transformants ont ensuite été criblés par imagerie de l’émission de fluorescence de la chlorophylle sur leur capacité à réaliser des transitions d’état. Plusieurs mutants de transitions d’état ont été ainsi isolés, et le séquençage a révélé que les mutations impliquées étaient concentrées sur la boucle stromale fg de la sous-unité IV. La mutagénèse dirigée de plusieurs résidus clés de la boucle fg a montré que les substitutions des résidus Asn122, Tyr124 et Arg215 généraient des mutants bloqués à l’état I indépendamment de l’état redox du pool de quinones. Des expériences d’interaction protéine-protéine ont ensuite servi à prouver que le domaine kinase de Stt7 interagit avec la boucle fg de la sous-unité IV et que son activité d’autophosphorylation dépend du résidu Arg125. Nous proposons un modèle de l’interaction entre ces deux protéines ainsi que du mécanisme d’activation de la kinase médié par le cyt b6fTo optimize photosynthetic efficiency in ever-changing light conditions, organisms of the green lineage regulate the distribution of energy input between the two photosystems through state transitions. Through a yet unknown mechanism, the cytochrome (cyt) b6f complex detects these redox changes and transmits a signal to the state transition kinase Stt7 for its activation. In order to decipher the role of the cyt b6f, we devised a novel experimental strategy in Chlamydomonas reinhardtii combining the random mutagenesis of a chloroplast gene by error-prone PCR, chloroplast transformation and selection of clones on phototrophic growth. Transformants were then screened by chlorophyll fluorescence emission imaging on their ability to perform state transitions. Several state transition mutants were isolated, and sequencing revealed that mutations concentrated in the stromal fg loop of subunit IV. Site-directed mutagenesis of key fg loop residues showed that substitutions of Asn122, Tyr124 and Arg125 produced mutants that are blocked in State I independently of the redox state of the PQ pool and with no adverse effects on cyt b6f assembly and electron transfer activity. Protein-protein interaction studies provided evidence that the kinase domain of Stt7 interacts with the subunit IV fg loop and that its autophosphorylation activity depends on Arg125. We propose a model for the interaction between these two proteins as well as for the cyt b6f-mediated mechanism of Stt7 activation
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Fonseca, Rute A. Rodrigues da. "Computational studies on cytochromes P450." Tese, Porto : [s.n.], 2006. http://catalogo.up.pt/F?func=find-b&local_base=FCB01&find_code=SYS&request=000091449.
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Toursel, Catherine. "Clonage et expression des gènes codant pour les protéines mitochondriales cytochrome b et Hsp60 de Toxoplasma gondii." Lille 1, 1999. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1999/50376-1999-225.pdf.
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La différenciation de Toxoplasma gondii en ses formes tachyzoïtes ou bradyzoïtes est un mécanisme clé dans la pathogenèse du parasite. Alors que les fonctions de la mitochondrie sont largement définies dans d'autres organismes, elles sont peu connues chez T. Gondii et seraient régulées lors de la différenciation. Nous avons choisi d'aborder la fonctionnalité de la mitochondrie chez les tachyzoïtes et chez les bradyzoïtes par l'étude du gène mitochondrial codant pour le cytochrome b et du gène nucléaire codant pour le chaperon mitochondrial Hsp60. Les ADNc codant pour ces deux protéines ont été clonés et séquences. Pour la première fois, un ARNm de 1234 pb codé par l'ADNmt de T. Gondii a été amplifié. Il code pour une protéine de 368 AA, homologue aux cytochromes b. Pour l'Hsp60, deux ARNm de 2430 et 2442 pb ont été isolés. Ils ne divergent que sur leur extrémité 5’, sont codés par le même gène nucléaire et résultent d'un épissage alternatif. Un seul de ces messagers présente un cadre ouvert de lecture codant pour une Hsp60 de 575 AAElle est localisée dans la mitochondrie de T. Gondii et possède une préséquence N-terminale capable d'importer, in vivo, la protéine exogène CAT dans l'organite parasitaire. L'expression de ces gènes a été analysée dans les deux stades parasitaires. L'amplification de l'ARNm codant pour le cytochrome b chez les tachyzoïtes et chez les bradyzoïtes a ainsi démontré la transcription de l'ADNmt dans ces deux formes du toxoplasme. Quant à l'Hsp60, par RT-PCR semi-quantitative, une quantité plus abondante des deux types de messagers a été amplifiée chez les bradyzoïtes. En revanche, nous avons démontré que la protéine Hsp60 est exclusivement exprimée dans les formes virulentes tachyzoïtes en dépit de l'abondance des messagers chez les bradyzoïtes. De plus, nous avons confirmé que ce chaperon, absent des bradyzoïtes réapparaît lorsque ces derniers se différencient en tachyzoïtes. L'ensemble de ces résultats suggère une corrélation entre la différenciation de T. Gondii et la régulation des fonctions mitochondriales qui pourrait impliquer une altération dans le métabolisme des carbohydrates et/ou la production d'énergie
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Janse, van Rensburg Marike. "The role of the cytochrome B and cytochrome C oxidase III genes in the immune response of the South African abalone, Haliotis midae." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/4275.
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Includes abstract.Includes bibliographical references (leaves 80-89).
Although South Africa is the second largest producer of abalone outside Asia, the sustainability of the industry could be threatened by infectious diseases (Troell et ai., 2006). Probiotics are increasingly being viewed as an alternative to chemical and antibiotic treatments (Balcazar et al., 2006), and have been shown to improve the health of the South African abalone, Haliotis midae (Macey and Coyne, 2005). In order to establish better health management systems, and to implement alternative therapies such as probiotics, a better understanding of how the abalone immune system functions, and specifically how it responds to stimulation, is necessary. Two genes of the electron transport system, cytochrome b and cytochrome c oxidase III, were found to be upregulated in a cDNA microarray experiment performed on haemocytes from immunestimulated abalone (Arendze-Bailey, unpublished). The current study sought to confirm these results by semi-quantitative PCR and to further elucidate the roles of these genes, and thus the electron transport system, in the abalone immune response.
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Trujillo, Robert Greg. "Phylogenetics of the genus Scotophilus (Chiroptera: Vespertilionidae): perspectives from paternally and maternally inherited genomes with emphasis on African species." Diss., Texas A&M University, 2005. http://hdl.handle.net/1969.1/4337.
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Bats of the genus Scotophilus are distributed throughout sub-Saharan Africa, parts of southern and Southeast Asia, a majority of the Indomalayan Islands, Reunion Island, and Madagascar. The genus is composed of 14 recognized species with seven distributed throughout sub-Saharan Africa including: (S. dinganii (A. Smith, 1833), S. leucogaster (Cretzschmar, 1830), S. nigritellus de Winton, 1899, S. nigrita (Schreber, 1774), S. nucella Robbins, 1983, S. nux Thomas, 1904, and S. viridis (Peters, 1852). The remaining species include four from southern and southeast Asia (S. celebensis Sody, 1928; S. collinus Sody 1936; S. heathi (Horsfield, 1831); S. kuhlii Leach, 1821), two on Madagascar (S. sp. nov. Goodman et al., in press; and S. robustus Milne-Edwards, 1881), and one endemic to Reunion Island (S. borbonicus (E. Geoffroy, 1803). The systematics and taxonomy of this genus have been controversial and continue to be confusing. The genus is plagued with problems in species definition and the systematic relationships among members of the genus are poorly understood. The major goal of this study was to use a molecular phylogenetic approach to clarify some of the controversy and confusion surrounding the members of this genus. Nucleotide differences from mtDNA and the Y chromosome were used to examine phylogenetic patterns within Scotophilus. Based on these data two new species of Scotophilus were identified. Phylogenetically, African Scotophilus were found to comprise a monophyletic group with S. nux as the most basal African taxon. Overall, the Asian S. kuhlii was the most basal taxon. A distant relationship was identified between S. kuhlii and S. heathi, the other Asian species examined. The multiple origins of Malagasy Scotophilus are apparent as the two Malagasy taxa in the study do not share a sister-group relationship. The large bodied S. nigrita is closely related to S. dinganii and the S. dinganii-like species all share a close relationship. S. nigrita has a S. dinganii-like mtDNA haplotype and a very distinct zfy haplotype, suggesting a possible hybridization event with a S. dinganii-like ancestor.
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Davis, Shawn Marit. "The involvement of cytochrome B¦5 in 16-androstene steroid synthesis in pig testis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ31823.pdf.
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Stroebel, David. "Détermination structurale du complexe du cytochrome b6f par cristallographie aux rayons X." Paris 7, 2004. http://www.theses.fr/2004PA077228.
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Cordeiro, Juçara Albina da Silva Gomes. "Sistemática Molecular de Thaptomys Thomas, 1916 (Rodentia, Cricetidae)." Universidade Federal do Espírito Santo, 2008. http://repositorio.ufes.br/handle/10/5717.
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Previous issue date: 2008-02-20Thaptomys is a monotypic genus. Thaptomys nigrita is only species recognized to the genus to the moment, although the taxonomic history of genus reveals more than one species has been described in the literature. Currently, there are four scenarios presented in taxonomic literature for the genus: 1) A single species, without subspecies, with wide geographical distribution, 2) One species with two subspecies, being Thaptomys nigrita nigrita distributed between southern of Bahia to northern of Santa Catarina and Thaptomys nigrita subterraneus distributed south of São Paulo to the north of Rio Grande do Sul, including eastern of Paraguay and northeastern of Argentina; 3) Two species with karyotype distinction, being Thaptomys sp. restricted to the south of Bahia with 2n = 50 and Thaptomys nigrita occurring in the rest of the genus distribution with 2n = 52, 4) Two species with morphological differentiation and one variant form, being Thaptomys sp. found in southern of Bahia and Thaptomys nigrita represented by the individuals found in the rest of the distribution of the genus, and a variant form found in Paraná. Thus, the objective of this study was to evaluate the four scenarios to the genus Thaptomys using molecular markers, and to test the existence of more than one taxonomic unit for the genus, from the study of 833 bp of nuclear gene cytochrome b (cit b). For this, we used population genetics analyzes, phylogenetic analyzes and analyzes of molecular variation (AMOVA). Our results revealed that the populations of the ends of the distribution are balanced demographic and population center of the distribution are expanding population. The time since the expansion reveal that the northern populations expanded to southward and southern populations expanded to northward. Phylogenetic analyzes and AMOVA reveal the existence of four evolutionarily significant units. Thus, we propose the existence of four taxonomic units for the genus Thaptomys: Thaptomys sp1, with 2n = 50 to the south of Bahia, Thaptomys nigrita to Espírito Santo, Minas Gerais, Rio de Janeiro and north of São Paulo, with 2n = 52; Thaptomys sp 2 to the center and east of São Paulo and Thaptomys subterraneus to south of São Paulo to Rio Grande do Sul, including northeastern to Argentina
Thaptomys é um gênero monotípico, sendo Thaptomys nigrita sua única espécie reconhecida, embora a história taxonômica do gênero revele que mais de uma espécie já foi descrita na literatura. Atualmente, existem quatro cenários taxonômicos apresentados na literatura para o gênero: 1) Uma única espécie, sem divisão subespecífica, com grande distribuição geográfica; 2) Uma espécie com duas subespécies, sendo Thaptomys nigrita nigrita distribuída entre o sul da Bahia até o norte de Santa Catarina e Thaptomys nigrita subterraneus distribuída do sul de São Paulo até o norte do Rio Grande do Sul, incluindo o leste do Paraguai e o nordeste da Argentina; 3) Duas espécies com distinção cariotípica, sendo Thaptomys sp. restrita ao sul da Bahia com 2n=50 e Thaptomys nigrita ocorrendo no restante da distribuição do gênero com 2n=52; 4) Duas espécies, com uma forma variante, com diferenciação morfológica, sendo Thaptomys sp. encontrado no sul da Bahia e Thaptomys nigrita representado pelo indivíduos encontrados no resto da distribuição do gênero, e uma forma variante encontrada no Paraná. Dessa forma, o objetivo deste trabalho foi avaliar os quatro cenários de divisão do gênero Thaptomys utilizando marcadores moleculares, e testar a existência de mais de uma unidade taxonômica para o gênero, a partir do estudo de 833 pb do gene nuclear citocromo b (citb). Para isso foram feitas análises de variabilidade genética intrapopulacionais, análises de demográficas das populações, análises filogenéticas e análises de variação molecular interpopulacional (AMOVA). Nossos resultados revelaram que as populações das extremidades da distribuição de Thaptomys se encontram em equilíbrio demográfico e as populações do centro da distribuição estão em expansão populacional. Os tempos desde a expansão revelam que as populações do norte se expandiram em direção ao sul e as populações do sul em direção ao norte. As análises filogenéticas e as análises de AMOVA revelam a existência de quatro unidades evolutivamente significantes. Dessa forma, propomos a existência de quatro unidades taxonômicas para o gênero Thaptomys: Thaptomys sp1, com 2n=50 para o sul da Bahia, Thaptomys nigrita para Espírito Santo, Minas Gerais, Rio de Janeiro e norte de São Paulo, com 2n=52; Thaptomys sp 2 para o centro e leste de São Paulo e Thaptomys subterraneus para sul de São Paulo até o Rio Grande do Sul, incluindo o nordeste da Argentina
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Haldi, Maryann Louise. "RNA splicing in yeast mitochondria : genetic and molecular studies of the folded structures of two introns of the cytochrome b gene /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487259125221362.
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Gardim, Sueli. "Relação filogenètica entre sete espécies de Triatominae (Hemiptera, Reduviidae) da região Centro-Oeste do Brasil baseada no sequenciamento de genes mitocondriais /." Araraquara : [s.n.], 2010. http://hdl.handle.net/11449/95826.
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Orientador: João Aristeu da RosaBanca: João Aristeu da Rosa
Banca: Eunice Aparecida Bianchi Galati
Banca:Maria Tercilia Vilela de azeredo Oliveira
Resumo: A doença de Chagas tem como agente etiológico o protozoário Trypanosoma cruzi, cujos vetores pertencem à subfamília Triatominae. Os triatomíneos distribuem-se distribuídos por toda região Neotropical e epidemiologicamente se destacam as espécies dos gêneros Panstrongylus, Rhodnius e Triatoma. O gênero Triatoma é o mais numeroso e foi subdividido em complexos específicos de acordo com semelhanças morfológicas e distribuição geográfica de suas espécies. As sete espécies estudadas podem ser encontradas na região Centro-Oeste do Brasil, das quais seis pertencem ao subcomplexo matogrossensis (T. baratai, T. costalimai, T. guazu, T. matogrossensis, T. vandae e T. williami). A outra espécie, T. sordida pertence ao subcomplexo sordida. O objetivo deste estudo foi determinar a posição filogenética das sete espécies ocorrentes na região Centro-Oeste, por meio de comparação das sequências dos fragmentos citocromo b e 16S do DNA mitocondrial, visto que até o momento não foi determinada a posição de T. baratai e T. vandae com base em dados moleculares. Os exemplares avaliados são oriundos de colônias mantidas junto ao Insetário de Triatominae da Faculdade de Ciências Farmacêuticas/UNESP - Araraquara. Após a extração do DNA genômico e da amplificação dos fragmentos 16S e Cytb, procedeu-se o sequenciamento do DNA em sqüenciador automático, modelo ABI 377. As sequências obtidas juntamente com outras sequências (do mesmo fragmento) já disponíveis no GenBank, foram alinhadas com auxílio do programa Clustal W do BioEdit e as inferências filogenéticas foram conduzidas utilizando-se análises de parcimônia e de distância com o programa MEGA 3.1. De acordo com os resultados encontrados, T. costalimai mostrou-se mais distante das demais espécies e foi posicionada como grupo externo. As outras espécies distribuíram-se em dois grupos:.. (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The protozoan Trypanosoma cruzi, the etiologic agent of Chagas' disease, is transmitted by vectors that belong to the subfamily Triatominae. The triatomines are distributed throughout the Neotropical region and species from Panstrongylus, Rhodnius and Triatoma genus stand out epidemiologically. The Triatoma genus is the largest and was divided in specific complexes according to morphological similarities and geographical distribution of its species. The seven species studied can be found in the Central West Region of Brazil, of which six belong to the matogrossensis subcomplex (T. baratai, T. costalimai, T. guazu, T. jurbergi, T. matogrossensis, T. vandae and T. williami). The other specie, T. sordida belong sordida subcomplex. The aim of this study was to determine the phylogenetic position of the seven species from Central West Region by comparing the 16S and Cytb fragments sequences of the mitochondrial DNA, since so far not been given the position of T. baratai and T. vandae based DNA sequences. The specimens evaluated came from colonies maintained at the Insectarium of Triatominae, Faculdade de Ciências Farmacêuticas / UNESP - Araraquara. After extraction of genomic DNA and amplification of the 16S and Cytb fragments, it was sequenced in an automatic DNA sequencer, model ABI 377. The sequences obtained and other sequences (of the same fragment) already available in GenBank were aligned using the Clustal W program of BioEdit and the phylogenetic inferences were conducted using the analysis of parsimony and distance with the MEGA 3.1 program. According to the results, T. costalimai was more distant from other species and was placed as an outside group. Other species are distributed in two groups, the first comprising the species T. vandae very close to T. matogrossensis and external of these, T. sordida. The second group includes T. guazu strongly related to T. williami... (Complete abstract click electronic access below)
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Crowley, Louis J. "Structure-function studies of conserved sequence motifs of cytochrome b5 reductase." [Tampa, Fla] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0001913.
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Benosman, Haféda. "Etude par R.P.E. de protéines rédox multicentres flavocytochrome b et cytochromes c tétrahémiques /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376117509.
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Souabni, Hager. "Modulation de l’activité du flavocytochrome b₅₅₈ : étude fonctionnelle." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112036/document.
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Le complexe NADPH oxydase est un élément essentiel de l’immunité inné. Présent dans les cellules phagocytaires (neutrophile), sa fonction est de produire massivement, dans le phagosome, des anions superoxyde et générer ainsi des espèces encore plus réactives de l’oxygène qui vont détruire acides nucléiques, lipides et protéines des bactéries phagocytées. Le cœur membranaire catalytique du complexe NADPH oxydase est constitué d’un hétérodimère membranaire, le cytochrome b₅₅₈ (Cyt b₅₅₈). Après activation de celui-ci par les partenaires protéiques cytosoliques p47phox, p67phox, p40phox et Rac, une succession de réactions de transferts d’électron de part et d’autre de la membrane a lieu au sein du Cyt b₅₅₈ pour aboutir à la réduction du dioxygène de manière très contrôlée. Afin de mieux comprendre cette régulation, nous nous sommes d’abord intéressés aux stéreoisomères trans de l’acide arachidonique, activateur naturel de cet enzyme (cis), sur le fonctionnement de la NADPH oxydase et avons abordé cette étude parallèlement sur du Cytb₅₅₈ d’origine bovine présent dans des membranes de neutrophiles et dans des membranes de levures exprimant le Cytb₅₅₈ de manière hétérologue. Nous avons montré que la géométrie joue un rôle important sur l’activation du complexe enzymatique. Dans un deuxième temps, afin d’étudier le rôle de l’environnement membranaire sur le fonctionnement de la NADPH oxydase, nous avons déterminé les propriétés cinétiques et thermodynamiques de l’activité NADPH oxydase du Cytb₅₅₈ recombinant exprimé en levures, purifié, puis reconstitué en liposomes de composition lipidique variée. Après comparaison avec ces mêmes propriétés obtenues pour le Cytb₅₅₈ dans les membranes plasmiques et du réticulum endoplasmique de levures, nous avons montré que l’activité NADPH oxydase très sensible à la température peut être modulée par la composition et l’état physique de la membraneNADPH oxidase complex is a major actor of both antimicrobial host defense and inflammation by generating highly regulated superoxide anion, rapidly converted into reactive oxygen species (ROS). The NADPH oxidase complex consists of a heterodimeric integral membrane flavocytochrome b₅₅₈ and three cytosolic components p67phox, p47phox and p40phox, and the small GTP binding protein Rac. In response to a cellular stimulus, cytosolic proteins are recruited to the phagosomal membrane where they are assembled with the Cytb₅₅₈ to form the active NADPH oxidase. The aim of the work was to better understand the modulation of superoxide anion production by this enzyme. For this purpose, we performed experiments with both bovine neutrophil membranes and yeast membranes expressing the bovine recombinant Cytb₅₅₈. We first investigated the effect of the trans-isomerization of the cis-arachidonic acid, the activator of NADPH oxidase in vitro and showed that specific geometry of the activator plays an important role in the activation of the complex. We also studied the role of the membrane environment on the functioning of NADPH oxidase and determined the kinetics and thermodynamics of NADPH oxidase activity depending on the lipid composition of Cytb₅₅₈ proteoliposomes. Comparison with these properties obtained with recombinant Cytb₅₅₈ embedded into endoplasmic reticulum and plasma membranes, we showed that the NADPH oxidase activity is highly temperature dependent and can be modulated by the lipid environment and the physic state of the membrane