Thèses sur le sujet « Bacillus subtili »
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Kuntumalla, Srilatha. « Patterns of reactivity of lantibiotics subtilin and nisin with molecular targets in Bacillus cereus and Bacillus subtilis 168 ». College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2190.
Texte intégralThesis research directed by: Molecular and Cell Biology. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Beijer, Lena. « The glycerol regulon in Bacillus subtilis ». Lund : Dept. of Microbiology, Lund University, 1994. http://catalog.hathitrust.org/api/volumes/oclc/39775845.html.
Texte intégralSvensson, Birgitta. « Heme A synthesis in bacillus subtilis ». Lund : Dept. of Microbiology, University of Lund, 1995. http://books.google.com/books?id=RwdrAAAAMAAJ.
Texte intégralHägerhäll, Cecilia. « On the structure and function of succinate:quinone oxidoreductase using Bacillus subtilis as model organism ». Lund : Dept. of Microbiology, University of Lund, 1994. http://books.google.com/books?id=C-5qAAAAMAAJ.
Texte intégralHansson, Mats. « Tetrapyrrole synthesis in Bacillus subtilis ». Lund : Dept. of Microbiology, Lund University, 1994. http://books.google.com/books?id=pJBqAAAAMAAJ.
Texte intégralShariati, Parvin. « Nitrate respiration in Bacillus licheniformis and Bacillus subtilis ». Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/350.
Texte intégralLe, Thi Tam. « Proteomic signatures of Bacillus subtilis ». [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=984429247.
Texte intégralConnelly, Mariah Bindel. « Multicellular development in Bacillus subtilis / ». For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
Texte intégralLin, Daniel Chi-Hong 1972. « Chromosome partitioning in Bacillus subtilis ». Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85288.
Texte intégralEymard-, Vernain Elise. « Etude des interactions entre trois types de nanoparticules métalliques et une bactérie du sol, Bacillus subtilis ». Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAV065/document.
Texte intégralMetallic nanoparticles are used in variety of consumer products (solar screen, paint or medicine), which results in an increasing release of nanoparticles in the environment. There is a need of better evaluating their fate and impacts in the environment. Microorganisms are one of the first targets of nanoparticles in the environment. Most studies on microorganisms and bacteria have focused on cellular mortality, and did not take into account possible transformations of NPs in the environment, which modify their toxicity. This study is focused on model bacteria, Bacillus subtilis and three nanoparticles: Ag-NPs, ZnO-NPs and TiO2-NPs. We evaluate on one hand the impact of nanoparticles on the metabolism on the metabolism of Bacillus subtilis, and on the other hand the impact of Bacillus subtilis and of its secretome on the nanoparticles, both being mutually dependent
Dobinson, Katherine Frances. « A kinetic analysis of transcription initiation by the Bacillus subtilis sigma-43 RNA polymerase : the effect of the delta subunit ». Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/27000.
Texte intégralScience, Faculty of
Microbiology and Immunology, Department of
Graduate
Adams, Claire. « A study of bacteriophages from Bacillus licheniformis and Bacillus subtilis ». Thesis, Heriot-Watt University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359798.
Texte intégralSidiq, Karzan Rafiq. « Cell wall metabolism in Bacillus subtilis ». Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3243.
Texte intégralMat, Wai Kin. « Genetic code mutants of bacillus subtilis / ». View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?BICH%202007%20MAT.
Texte intégralFarquhar, R. « The spoIVC locus of Bacillus subtilis ». Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370251.
Texte intégralChaloner-Courtney, Iain James. « The spoIIA locus of Bacillus subtilis ». Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306497.
Texte intégralFitzgerald, A. V. M. « Production of bacilysin by Bacillus subtilis ». Thesis, University of Kent, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378626.
Texte intégralAllenby, Nicholas E. E. « The phosphate stimulon of Bacillus subtilis ». Thesis, University of Newcastle Upon Tyne, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405363.
Texte intégralSassine, Jad. « Cell wall synthesis in Bacillus subtilis ». Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3946.
Texte intégralBrown, James. « Cell wall morphogenesis in Bacillus subtilis ». Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3373.
Texte intégralDELATTRE, DELPHINE. « Phosphorylation des proteines chez bacillus subtilis ». Paris 7, 2000. http://www.theses.fr/2000PA077059.
Texte intégralTenesch, Aaron Chase. « The experimental silicification of bacillus subtilis ». Diss., [Missoula, Mont.] : The University of Montana, 2009. http://etd.lib.umt.edu/theses/available/etd-08292009-094408.
Texte intégralSamson, Jennifer Adele. « Engineering synthetic receptors in Bacillus subtilis ». Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/46167.
Texte intégralSan, Eustaquio Campillo Alba de. « Development of a functional screen for MreB mutants in Bacillus subtilis and characterization of a putative MreB effector ». Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS071/document.
Texte intégralAcquisition and maintenance of the bacterial shape has been conscientiously studied for a long time. Nevertheless, there are still many unanswered questions. Gram-positive bacteria present a rigid external coating (cell wall) that allows them to preserve internal osmotic pressure and cell morphology. The cell wall (CW) is mainly formed by the peptidoglycan meshwork (PG), that confers its structure to the CW, to which are connected teichoic acids. The absence of this essential barrier causes the loss of shape and, ultimately, lysis of the cells. Integrity of the CW is, therefore, a matter of vital importance for bacteria. Proper CW synthesis and structure depends on the so-called peptidoglycan elongation machineries (PGEM) in charge of building the PG meshwork. The precise composition and functioning of the PGEM is not completely understood but they rely on a key player: MreB, a conserved prokaryotic actin-like protein. MreB is suspected to control PGEM activity and/or assembly but its precise function and mode of regulation are currently unknown. I used Bacillus subtilis, the model for Gram-positive bacteria, to gain a better understanding of MreB functions via i- the development and use of a genetic screen for loss-of-function mutants of mreB and ii- the study of a potential effector of MreB.(i) MreB has been studied for almost two decades now and still, little is known about its function(s). Since biochemical approaches proved to be difficult so far, most of the studies have focused on cellular localization and dynamics of the protein. Here, I have designed a genetic screen by means of which I have obtained a collection of functionally impaired mreB mutants in B. subtilis. Characterization of these mutants revealed numerous key residues for the functioning of the protein. Interestingly, my results indicate that some mutants have kept their dynamic properties (suggesting functional association to the PGEM) together with a wild type shape, while being strongly affected for growth. Preliminary results indicate an impaired ability to use certain carbon sources linking MreB to cellular metabolism. This suggests the existence of either a checkpoint or a coupling between carbon metabolism and CW expansion in B. subtilis.(ii) Unpublished results from our group revealed the existence of an uncharacterized operon (ydcFGH), whose expression is highly induced in the absence of MreB by comparison to the wild type. I have 1- deciphered the cause of ydcFGH induction in the absence of MreB, revealing the existence of multiple mutations in the MreB strain and 2- realized a thorough characterization of each gene of the ydcFGH operon. Although the exact link between MreB and ydcFGH is yet unknown, my results suggest a potential role of YdcH in the control of carbon metabolism and adaptation to stationary phase. In light of my mutagenesis screen data (i), these results are pointing towards a strong link between MreB and carbon metabolism
Williams, Rachel C. « A comparative analysis of the Bacillus subtilis and Bacillus anthracis 'secretomes' ». Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270823.
Texte intégralFoucher, Anne-Emmanuelle. « Caractérisation biochimique de YphC, une protéine de Bacillus subtilis à deux domaines GTPases impliquée dans la biogenèse du ribosome ». Grenoble, 2010. http://www.theses.fr/2010GRENV040.
Texte intégralGenome sequencing programs have revealed many genes of unknown function. The systematic disruption of these genes revealed the essentiality for some of them. Studying orphan proteins became of first importance as they are ideal targets for new antibacterial compounds. YphC is a GTPase from Bacillus subtilis that meets these criteria. It is well conserved throughout bacterial kingdom but is not found in eukaryota or archeas, strengthening the choice of this protein as a future target for antibacterial drugs. YphC has the particularity to possess two GTPase domains in tandem. As a unique protein, we decided to study YphC from a biochemical point of view to better understand its catalytic mechanism. We overexpressed and purified the protein, either wild type or mutants. We measured its enzymatic constants and characterize potassium activation effect on its hydrolytic activity. We showed that YphC displays a high GTPase activity and that GD1 bears the majority of this activity. GD2 would thus have a regulatory role in the protein. We also studied the role of YphC in vitro. We showed that the protein was able to interact with ribosome from Bacillus subtilis in a nucleotide dependant manner, suggesting that YphC plays a role in ribosome biogenesis
Crum, Morris G. (Morris Glenn). « Some Responses of Bacillus subtilis Spores to Glutaraldehyde ». Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc331507/.
Texte intégralPiedrahita-Aguirre, Cesar Augusto 1980. « Estudo da produção de iturina por bacillus subtilis, em fermentação semi-sólida utilizando como substrato farelos de soja, arroz, trigo e casca de arroz = Study of production of iturin by Bacillus subtilis in solid state fermentation using as substrate soybean meal, rice meal, wheat bran and husk rice ». [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255474.
Texte intégralTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Este trabalho se propôs a estudar a produção da iturina A por Bacillus subtilis em fermentação semi-sólida em biorreatores de leito empacotado. O trabalho foi desenvolvido em quatro partes. Em uma primeira parte foi feito um screening com cepas silvestres e seus mutantes obtidos a partir da exposição de luz UV e acridina laranja. A cepa Bacillus subtilis subsp. subtilis NRRL NRS-1270 foi a que apresentou maior atividade antagônica contra os fungos Aspergillus fumigatus Fresenius NRRL 164, Aspergillus fumigatus Fresenius NRRL 166 e Aspergillus flavus var. oryzae NRRL 484. O extrato metanólico obtido da fermentação semi-sólida do Bacillus subtilis subsp. subtilis NRRL NRS-1270 foi analisado através da espectrometria de massas encontrando-se lipopeptídeos com massa molecular entre m/z 1021,43 e m/z 1087,48, mas sem a presença da iturina A. Em uma segunda etapa a cepa Bacillus Iso 1 foi isolada a partir das raízes de soja, e ante a dificuldade de identificar a iturina A através da cromatografia liquida de alta eficiência (HPLC), foi desenvolvida a metodologia de purificação da iturina A utilizando a cromatografia em coluna de vidro preenchida com sílica gel 60. A iturina A foi eluída com três sistemas de solventes compostos por 20 mL de clorofórmio-metanol-água (65:25:4,v/v/v), fração 1, seguido de 20 mL de clorofórmio-metanol-água (30:50:10, v/v/v), fração 2, e a fração final composta por 10 mL de clorofórmio-metanol-água (20:60:15, v/v/v). As frações obtidas foram analisadas através da HPLC e da espectrometria de massa, identificando 5 isômeros da iturina A (C13-C16). Na terceira etapa, foi feito um delineamento composto central rotacional (DCCR) para avaliar o efeito da casca de arroz como suporte inerte e da vazão volumétrica de ar na produção de iturina A; como substratos foram utilizados o farelo de soja desengordurado e o farelo de trigo. Nenhuma variável do DCCR foi estatisticamente significativa, mas operacionalmente foram importantes, devido à redução da oxigenação do Bacillus Iso 1 pela baixa vazão de ar e menor concentração de casca de arroz, favorecendo a produção de iturina; nestas condições obteve-se 6,88 g/kg de substrato seco de iturina A.Esta é a maior quantidade de iturina A produzida em biorreatores de leito empacotado (coluna) com aeração forçada até hoje. Na quarta etapa, a partir dos resultados obtidos no DCCR foram estudados os parâmetros do processo: queda de pressão, consumo de oxigênio e perfis de temperatura, visando entender o comportamento da fermentação a 0,4 L/min e 0,8 L/min. A máxima produção de iturina obtida foi 5,58 g/kg de substrato seco com a vazão de 0,4 L/min. O incremento na queda de pressão é ocasionado não unicamente pelo incremento da vazão volumétrica, mas também pela produção do biopolímero ?-PGA o qual ocupa os espaços livres entre as partículas, dificultando o fluxo normal de ar através do leito, reduzindo o consumo de oxigênio. A baixa oxigenação favoreceu a alta produção da iturina A e gerou baixo calor metabólico (5,75 W/kg-dry substrato·min). Os resultados obtidos podem ser úteis na elaboração de estratégias para ampliação de escala do processo em fermentadores aerados de leito empacotado
Abstract: This work covers a study of the production of iturin A by Bacillus by solid-state fermentation in packed bed bioreactors. The study was conducted in four parts. At first a screening was conducted with wild strains and their mutants obtained from exposure to UV light and mutagenic agent acridine orange. The strain Bacillus subtilis subsp subtilis NRRL NRS 1270 showed the highest antagonistic activity against Aspergillus fumigatus NRRL 164, Aspergillus fumigatus NRRL 166 and Aspergillus flavus var . oryzae NRRL 484. A methanolic extract obtained by solid state fermentation of Bacillus subtilis subsp subtilis NRRL NRS 1270 was analyzed with mass spectrometry showing lipopeptides with molecular mass between m/z 1021.43 and m/z 1087.48, but without the presence of iturin A. In the second stage, the strain Bacillus Iso 1 was isolated from soybean roots. Given the difficulty of identifying iturin A by high performance liquid chromatography (HPLC), a iturin A purification methodology was developed using glass column chromatography packed with activated Silica gel 60 and alumina. This methodology involved three solvent systems for elution of the iturin A from the column. A first fraction consisted of 20 ml of chloroform-methanol-water (65:25:4 , v/v/v) and was followed by 20 ml of chloroform - methanol- water (30:50 : 10, v/v/v), that was then followed by a final fraction consisting of 10 ml of chloroform-methanol-water (20:60:15, v/v/v). The fractions obtained of fermentation were analyzed by both HPLC and mass spectrometry, identifying five iturin A isomers (C13-C16). In the third stage of the study, an experimental design was constructed in the form of a central composite rotational design (CCRD) to evaluate the effect of rice husk as an inert support and air flow rates to the iturin A production, using defatted soybean meal and wheat bran as substrate. Although none of the studied variables showed statistical significance, the operational importance of reduction of oxygenation of the Bacillus Iso 1 fermentation due to the low concentration of rice husk and air flow rate was observed to favor the production of iturin; in these conditions high productivity was obtained reaching 6.88 g/kg-dry substrate of iturin A. Concluding from available literature, this is the highest concentration of iturin A ever produced in packed bed bioreactor (column) with forced aeration to date. In the fourth stage, in order to understand the behavior of the fermentation under aeration conditions between 0.4 L/min and 0.8 L/min, the following process parameters were studied, based on the results obtained from the CCRD: pressure drop, oxygen consumption and temperature profiles. The maximum production of iturin obtained was 5.58 g/kg-dry substrate with the air flow rate at 0.4 L/. The increase of the pressure gradients is caused not only by increasing the volumetric air flow rate but also by the production of biopolymer ?-PGA by Bacillus iso 1, which occupies the free interparticle space, hindering or preventing the normal flow of air through the bed and thus leading to reduced oxygen consumption. The low oxygenation favored the high iturin A production and resulted in low metabolic heat generation (5.75 W/kg-dry substrate.min). The results of this work are expected to be conducive for designing strategies to scale up the process in aerated packed bed bioreactors
Doutorado
Engenharia de Alimentos
Doutor em Engenharia de Alimentos
Angus, Christine. « The implications of plant/bacterial interactions for the phytoremediation of Cs¹³ⷠ». Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275424.
Texte intégralCarvalho, Filho Celso Duarte. « Utilização do bioteste com esporos de Bacillus subtilis na avaliação da integridade asseptica de embalagens flexiveis esterilizaveis ». [s.n.], 1996. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255401.
Texte intégralDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Este trabalho teve por finalidade avaliar a integridade asséptica da selagem de topo das bolsas esterilizáveis, composta de um laminado de polipropileno (70µm), folha de alumínio (9µm), náilon (15µm) e poliéster (12µm) através de bioteste com esporos de Bacillus subtilis e, também, estabelecer o processo térmico adequado para produzir purê de banana comercialmente estéril nestas embalagens, processadas em autoclave por imersão total em água quente com sobrepressão. O produto selecionado foi purê de banana natural, variedade "nanica" {Musa cavendish, Lamb.) com pH 4,6 -4,7 embalado (130g) em bolsas esterilizáveis de 130 x 170mm. Microfuros de diversos diâmetros foram intencionalmente formados nestas bolsas através de fios de níquel-cromo colocados na área de selagem de topo. Após autoclavagem, os fios foram retirados das embalagens e estas foram submetidas assepticamente a um contato direto com uma suspensão de esporos da referida bactéria durante 1 hora. Foi analisado o poder de penetração dos esporos através de diferentes diâmetros de microfuros formados pelos fios na área de selagem de topo das embalagens (diâmetros dos fios : 32, 48, 79 e 97µm). O bioteste foi aplicado em bolsas cheias antes e após o processo térmico do purê a 115°C. A penetração e crescimento do B. subtilis foi confirmada por ensaios bioquímicos e subcultura em meio agar nutriente, com prévia incubação das bolsas a 30°C por 7 dias. Estas embalagens foram posteriormente submetidas ao teste eletrolítico para confirmação dos microfuros detectados. O processo térmico adequado para o purê de banana, previamente inativado enzimaticamente (97°C por 5 min.), foi de 7,5 min. a 115°C equivalente a um Fo de 0,64 min., verificado pelo método geral e ensaios de esterilidade comercial. Foi notado que o processo térmico favoreceu a penetração dos esporos através de microfuros de menor diâmetro, pois enquanto que o bioteste detectou microfuros >= 79µm m com 87,5% de penetração antes do processo, o mesmo teste detectou penetração em microfuros >= 48µm de diâmetro com 53,8% de penetração em bolsas testadas após o processo. O teste eletrolítico só foi capaz de detectar microfuros formados com fios de 79um de diâmetro em 69,23% das amostras. Em ensaios realizados antes e depois do processo térmico não foi detectada penetração em bolsas com microfuros formados com fios de 32µm .
Abstract: The aim of this work was to evaluate the integrity of the top sealing area of retortable pouches formed by a laminate of polypropylene (70 µm), aluminum foil (9um), nylon (15 µm) and polyester (12 µm), using Bacillus subtilis spores as a biotest and also to establish the proper thermal process in order to produce comercially sterile banana puree, packed in pouches processed in a full water-immersion retort. The selected product was banana puree (130g), variety "nanica" (Musa cavendish, Lamb.), pH 4.6 - 4.7, packed in 130 x 170mm retortable pouches. Microholes of different diameters were intentionally made with nickel-chrome threads placed in the top seal area. After sterilization, the threads were withdrawn from the seals and the packages were tested using the spore test. A suspension of B. subtilis spores was aseptically left on the top seal for 1 hour. The capacity of the spores to penetrate through different microholes diameters (32, 48, 79 and 97 µm) was evaluated. The biotest was carried out before and after processing the banana puree at 115°C. Bacillus subtilis penetration and growth was confirmed by biochemical tests and subculture in nutrient agar after incubation of the pouches at 30°C for 7 days. The tested packages were, latter, submitted to eletrolitic test for microholes confirmation. The proper thermal process for banana puree, previously bleached (97°C for 5 min.), was 7,5 min. at 115°C equivalent to an Fo of 0,64 min., confirmed by the general method evaluation and commercial sterility tests. It was noted that heat processing favored the penetration of spores at lower microholes sizes:while the spore test detected microholes of >= 79 µm with 87,5% of penetration before processing, the same test detected penetrations through microholes >= 48 µm with 53,8% penetration after processing. Eletrolitic test was only able to detect microholes formed with 79 µm diameter threads, showing presence of microholes in 69,23% of the tested samples. No penetration was detected in pouches with microholes formed with 32um tested before or after heat processing.
Mestrado
Mestre em Ciência de Alimentos
Charbonnier, Teddy. « Transport du pyruvate et régulations du métabolisme central par le malate chez Bacillus subtilis ». Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS076/document.
Texte intégralIn Bacillus subtilis like for all the bacteria, the central carbon metabolism is essential for growth. It uses glucose (a glycolytic carbon source) and malate (a gluconeogenic carbon source) as preferential carbon sources. These two carbon sources are able to induce carbon catabolite repression through the transcription factor CcpA and thus establishing a hierarchy in the use of alternative carbon sources. The pyruvate is in the middle of the carbon metabolism, and can be used by B. subtilis as sole carbon source; however its transporter remains unknown.Transcriptome analyses revealed that the only operon specifically expressed in cells grown on pyruvate is ysbAB, and we showed that its deletion led to a strong growth defect on pyruvate. Using tagged proteins, we highlighted that YsbA and YsbB formed a complex localized at the membrane. We next showed that this complex is the major pyruvate transporter, and operates as a facilitated transporter. Using a reporter fusion, we showed that the operon lytST located upstream of ysbAB, and coding for a two-component system, is responsible for the induction of ysbAB. We also showed that besides the CcpA-mediated repression by both glucose and malate, an additional regulation mechanism through the malic enzyme activity of MaeA is acting on ysbAB. This regulation is due to the accumulation of pyruvate in the cell which hinders the LytST-mediated induction of ysbAB.We also showed that a CcpA-independent repression is exerted on dctP, the gene coding for the succinate and fumarate transporter, in the presence of malate, suggesting a regulation mechanism similar to the one observed for ysbAB. Finally, we showed that the metabolic flux going through MaeA is also involved in the CcpA-dependent repression of the genes coding for glycolytic transporter in presence of malate
Schönert, Stefan. « Maltose- und Maltodextrin-Verwertung in Bacillus subtilis ». [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973091967.
Texte intégralBernard, Rémi. « Résistance à la bacitracine chez Bacillus subtilis ». Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2007. http://tel.archives-ouvertes.fr/tel-00350345.
Texte intégralLe groupe des Firmicutes, dont la bactérie modèle est Bacillus subtilis, est un groupe ubiquitaire producteur d'antibiotiques et contenant de nombreux organismes pathogènes. Les analyses effectuées au laboratoire ont permis d'identifier chez les Firmicutes des systèmes associant un phosphorelais et un transporteur ABC. Dans chacun des cas, les gènes codant les différents partenaires du système sont à proximité sur le chromosome et le phosphorelais régule l'expression des gènes codant le transporteur ABC. On trouve trois de ces systèmes chez B. subtilis nommés BceRSAB (anciennement YtsABCD), YvcPQRS et YxdJKLM. L'objectif de notre étude était de tester l'hypothèse selon laquelle ces systèmes pouvaient être impliqués dans la résistance aux antibiotiques ciblant l'enveloppe bactérienne.
La bacitracine est un antibiotique qui se complexe à l'undécaprényl pyrophosphate (UPP) et inhibe la dernière étape de la biosynthèse du peptidoglycane : la régénération de l'undécaprényl phosphate (UP). Nos résultats indiquent que le système BceRSAB est le composant majeur de la résistance à la bacitracine chez B. subtilis. L'expression de l'opéron bceAB est activée, en présence de bacitracine, par le phosphorelais BceRS. Nous avons également identifié une protéine, nommée BcrC, qui participe à la résistance à la bacitracine chez B. subtilis. Nous avons démontré que cette dernière est une UPP phosphatase impliquée dans la régénération de l'UP et s'oppose ainsi à l'action de la bacitracine. L'expression du gène bcrC ne dépend pas du phosphorelais BceRS mais de trois facteurs sigma à fonction extracytoplasmique. En conclusion, B. subtilis possède deux types de systèmes de résistance à la bacitracine indépendants et complémentaires.
Nous avons par la suite analysé le mécanisme de régulation de l'induction du système BceRSAB par la bacitracine. Nos résultats sont surprenants et montrent clairement que le transporteur ABC BceAB participe à l'activation de l'expression de ses propres gènes de structure avec le phosphorelais BceRS. De plus, lorsque le pool cellulaire d'UPP diminue (lorsque la phosphatase BcrC est surproduite), et en présence de bacitracine, l'expression du gène bceA diminue également. Ceci montre que l'UPP participe, avec la bacitracine, au stimulus du système BceRSAB. Notre hypothèse de travail est que le transporteur ABC, prédit comme étant un exporteur, prend en charge le complexe UPP/bacitracine et agit comme une flippase pour créer une dissymétrie membranaire ressentie par le senseur BceS. Il n'est pas exclu, qu'en présence de bacitracine, le transporteur BceAB puisse interagir avec le senseur BceS pour permettre l'activation du système.
La majeure partie des bactéries du groupe des Firmicutes possède, d'une part, des protéines similaires à BcrC, et, d'autre part, des systèmes similaires au système BceRSAB. Toutes les protéines « BcrC-like » ont un motif caractéristique permettant de les classer dans la famille des phosphatases de type PAP2. Il est tentant de penser qu'elles sont toutes des UPP phosphatases assurant une des étapes clés de la synthèse du peptidoglycane.
Par ailleurs, les deux autres systèmes « Bce-like » de B. subtilis, YvcPQRS et YxdJKLM, sont également activés en présence d'antibiotiques ciblant l'enveloppe bactérienne et nous savons que le transporteur ABC YvcRS est aussi impliqué dans le mécanisme de régulation. Nous proposons donc que les systèmes « Bce-like » des Firmicutes sont tous des systèmes de détoxification dirigés contre des antibiotiques ciblant l'enveloppe bactérienne.
Xu, Meizhu. « Functional analysis of PBP2b in Bacillus subtilis ». Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491605.
Texte intégralWolf, Diana. « Das Phagenschock-Protein LiaH aus Bacillus subtilis ». Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-151553.
Texte intégralMoresoli, Christine. « The production of surfactin by Bacillus subtilis / ». Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65329.
Texte intégralJayaraman, Padmavathy. « Analysis of Bacillus subtilis 1604 spore germination ». Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317752.
Texte intégralWilkinson, Jonathan Frome. « Regulation of sigmaF activity in Bacillus subtilis ». Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300121.
Texte intégralHall, Andrea. « Bacillus subtilis oxalate decarboxylase : roles and regulation ». Thesis, University of East Anglia, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426696.
Texte intégralRadford, David S. « Copper and zinc homeostasis in Bacillus subtilis ». Thesis, University of Newcastle Upon Tyne, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427302.
Texte intégralCoxon, Rosemary D. « Factors affecting protein export from Bacillus subtilis ». Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287424.
Texte intégralMackichan, Calum. « Organization of secretion components in bacillus subtilis ». Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112122.
Texte intégralIn the years since the cloning of GFP, the field of bacterial cell biology has characterized a variety of specific protein localization patterns in the bacterial membrane. The vast majority of early subcellular localization studies made use of inducible GFP fusions, which generally required the presence of high concentrations of inducer, and can therefore be considered to be overexpressed. An outstanding question remains over the organization of natively expressed proteins in the membrane. Here, we have investigated the localization of functional GFP fusions to proteins catalyzing important membrane processes; the secretion motor protein SecA, the membrane insertase YidC1, and the essential phospholipid synthase PgsA using total internal reflection fluorescence microscopy (TIRFM). This allowed natively expressed proteins to be localized with temporal resolution that can capture their dynamics. We characterized dynamic complexes dispersed throughout the membrane displaying diffusive movement with no preferred trajectories. Further characterization focused upon identifying conditions in which the localization pattern was disturbed. A polar mislocalization was identified in a cardiolipin mutant strain. The yeast two-hybrid (Y2H) approach is a robust approach to detect binary interactions on a proteome-scale. We performed genome-wide Y2H screens as well as targeted Y2H analyses for specific interactions involving components of the Sec and Tat secretion machineries of B. subtilis, revealing an intricate protein-protein interaction network involving 71 proteins. Furthermore, three proteins identified in the Tat network, WprA, CsbC and HemAT, were shown to be important for effective protein secretion via the B. subtilis Tat system, indicating that our yeast two hybrid assays reveal biologically significant interactions involving membrane proteins. The studies provide a novel proteomic view on the interaction network of the secretion systems of B. subtilis
Souza, Renata Damasio de. « Esporos de Bacillus subtilis como adjuvante vacinal ». Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/42/42132/tde-24022015-124003/.
Texte intégralBacillus subtilis spores have been shown to behave as vaccine adjuvants, promoting the increase of antibody responses after co-administration with antigens either admixed or adsorbed on the spore surface. Nonetheless, such specialized application requires highly purified spore preparations at high yields. In this work, we successfully performed a systematic quantitative analysis of sporulation conditions and spore purification methods, which improved the reproducibility of the process and the obtainment of samples with high purity and yield. Afterwards, we further evaluated the immune modulatory properties of these spores using a recombinant HIV-1 Gag-p24 protein as a model antigen. The co-administration, but not adsorption to the spore surface, enhanced the immunogenicity of that target antigen, without inducing deleterious effects, after subcutaneous administration to BALB/c and C57BL/6 mice. Besides promoting activation of antigen presenting cells, spores interact with receptors related to innate immunity, due to the absence of the adjuvant effect on TLR2 knockout mice. These results open interesting perspectives for the use of B. subtilis spores as vaccine adjuvants.
Deloupy, Alexandre. « Expression stochastique des gènes chez Bacillus subtilis ». Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS443.
Texte intégralA population of genetically identical individuals sharing the same environment exhibits some residual phenotypic variability. Such heterogeneity arises from the stochastic, or random, nature of gene expression also referred as noise. This stochasticity results on the one hand from the random encounter of chemical species during both transcription and translation (intrinsic noise), and on the other hand from the fluctuations in the concentration of these chemicals (extrinsic noise). A stochastic model involving only intrinsic noise predicts that phenotypic noise strength varies linearly with translational efficiency but does not depend on transcriptional one. This prediction was shown to be compatible with data on a limited number of strains and conditions but has never been fully tested on a large collection of strains with different transcription and translation efficiencies. We aim to go further in the test of this prediction by using a collection of ~40 strains of the bacterium Bacillus subtilis where GFP is expressed under the control of different Promoters, TSS and RBS. For each strain, cell-to-cell heterogeneity is investigated by quantifying fluorescence signal at the single cell level, based on flow cytometry techniques and epifluorescence microscopy. Our results show that, contrary to expectations, phenotypic noise strength shows a strong positive correlation with transcriptional efficiency. We demonstrated that over a wide range of expression covering most of the proteome of B. subtilis, the expression noise is dominated by external noise sources. Therefore, stochastic models of gene expression are not suitable for quantifying the effects of translation and transcription on gene expression noise
Pujic, Petar. « Etude systematique du chromosome de bacillus subtilis ». Paris 7, 1997. http://www.theses.fr/1997PA077269.
Texte intégralBernard, Rémi Pierre. « Résistance à la Bacitracine chez Bacillus subtilis ». Aix-Marseille 2, 2007. http://theses.univ-amu.fr.lama.univ-amu.fr/2007AIX22028.pdf.
Texte intégralMinami, Hiromichi. « Studies on γ-glutamyltranspeptidase of Bacillus subtilis ». Kyoto University, 2003. http://hdl.handle.net/2433/149004.
Texte intégral0048
新制・課程博士
博士(農学)
甲第10281号
農博第1353号
新制||農||870(附属図書館)
学位論文||H15||N3802(農学部図書室)
UT51-2003-H702
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 熊谷 英彦, 教授 加藤 暢夫, 教授 村田 幸作
学位規則第4条第1項該当
Davies, Ashley. « Peptidoglycan architecture and dynamics in Bacillus subtilis ». Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/8322/.
Texte intégralSanders, Rhiannon. « Segregational stability of plasmids in Bacillus subtilis ». Thesis, University of Warwick, 1986. http://wrap.warwick.ac.uk/109832/.
Texte intégralSlavíčková, Radka. « Optimalizace produkce vybraných enzymů pomocí Bacillus subtilis ». Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2012. http://www.nusl.cz/ntk/nusl-216884.
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