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Oxley, David. "Surface polysaccharides of Serratia marcescens." Thesis, University of Hull, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252968.
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Brigden, C. J. "Surface carbohydrates of Serratia marcescens." Thesis, University of Hull, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375628.
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Jessop, Helen L. "The immunochemistry of serratia marcescens." Thesis, Aston University, 1986. http://publications.aston.ac.uk/12463/.
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Yan, Qiang. "Metabolic Engineering of Serratia marcescens." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5348.
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The potential value of the chitin biomass (e.g. food waste) is recently considered being ignored by landfill. Chitin can be a potential cheap carbon source for converting into value-added chemicals by microorganisms. Serratia marcescens is a chitinolytic bacterium that harbors endogenous chitinase systems. With goals of characterzing S. marcescens chitinolytic capabilities and applying S. marcescens to chemical production from chitin, my dissertation main content includes five chapters: 1) Chapter 1 highlights background information of chitin source, S. marcescens and potential metabolic engineering targets using chitin as a substrate; 2) Chapter 2 demonstrates that ChiR is a key regulator in regulating 9 chitinase-related genes in S. marcescens Db11 and manipulation of chiR can be a useful and efficient genetic target to enhance chitin utilization; 3) Chapter 3 reports the production of N-acetylneuraminic acid (Neu5Ac) from chitin by a bottom-up approach of engineering the nonconventional chitinolytic bacterium, Serratia marcescens, including native constitutive promoter characterization and transcriptional and translational pathway balancing; 4) Chapter 4 describes improvement of S. marcescens chitinolytic capability by an adaptive evolution approach; 5) Chapter 5 elucidates S. marcescens intracellular metabolite profile using a constraint-based genome-scale metabolic model (iSR929) based on genomic annotation of S. marcescens Db11. Overall, the dissertation work is the first report of demonstrating the concept of chitin-based CBP using S. marcescens and the computational model and genetic molecular tools developed in this dissertation are valuable but not limited to design-build-test of S. marcescens for contributing to the field of biological science and metabolic engineering applications.
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Silva, Cristina Ferraz. "Produção biotecnologica de surfactante por Serratia marcescens." [s.n.], 2002. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256676.
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Orientador: Glaucia Maria PastoreDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Biosurfactantes são compostos produzidos por microrganismos os quais possuem em sua molécula uma porção hidrofilica (solúvel em água) e uma porção hidrofóbica (insolúvel em água). Essas moléculas são capazes de reduzir a tensão superficial e interfacial em ambas soluções aquosas e misturas de hidrocarbonetos, as quais fazem desses compostos potenciais candidatos para aumentar a recuperação de óleo e processos de deemulsificação. No presente trabalho foi estudada a produção de biosurfactante por uma linhagem de bactéria. O microrganismo considerado foi pré-selecionado como produtor de biosurfactante em trabalhos anteriores e identificado nesta dissertação como Serratía marcescens. As melhores condições para produção do biosurfactante em agitador rotativo foram determinadas através do processo de otimização utilizando Planejamento Experimental. Além disso, foram estudadas algumas propriedades do biosurfactante, como por exemplo, capacidade emulsificante e estabilidade em diferentes pHs e temperaturas. Finalmente, testou-se a aplicação do biosurfactante produzido avaliando-se o efeito da sua adição na atividade de lipase de Rhízopus sp. quando comparado ao efeito produzido por surfactantes químicos.
Abstract: Biosurfactants are compounds produced by microrganisms those molecules include a hydrophilic portion (water soluble) and a hydrophobic portion (water insoluble). These molecules are capable of reducing surface and interfacial tensions in both aqueous solutions and hydrocarbon mixtures, which makes them potential candidates for enhancing oil recovery and deemulsification processes. Biosurfactant production by a bacterial strain was studied in this work. The microrganism considered was isolated in previous studies and identified in this work as Serratia marcescens. The best conditions for biosurfactant production in shake flasks were determined through an optimization process using an Experimental Design. Móreover, some properties of the biosurfactant were studied, for example, its emulsifying capacity and stability at different pH values and temperatures. Finally, the application of the biosurfactant produced was tested evaluating the effect of its addition on the activity of Rhizopus sp. Lipase, as compared to the effect produced by chemical surfactants.
Mestrado
Mestre em Ciência de Alimentos
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Perrakis, Anastassis. "Structural studies of chitinase A from Serratia marcescens." Thesis, University of York, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307167.
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Hamilton, Jaeger. "Secretion of the chitinolytic machinery in Serratia marcescens." Thesis, University of Dundee, 2013. https://discovery.dundee.ac.uk/en/studentTheses/7f7a0d4f-1ac2-4ca1-81fc-459d5ec87712.
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There are six known secretion systems in Gram negative bacteria, referred to as Type 1 to Type 6 respectively, which are dedicated to moving substrate across the outer membrane. Secretion systems are broadly separated into those that move their substrate across the cell envelope in a single translocation event (one-step systems), and those that are dependent on the Sec or Tat machineries for export to the periplasm (two-step systems). Serratia marcescens is an important opportunistic human pathogen and has gathered a lot of interest due to its repertoire of secreted proteins. These include the haem-scavenging protein HasA, which is secreted by a Type 1 secretion system, and the cytotoxic haemolysin ShlA, which is secreted as part of a two-partner Type 5 secretion system. Serratia marcescens also encodes a Type 6 secretion system, which is known to translocate at least six effector molecules directly into other bacterial target cells. Serratia marcescens is a model organism in terms of its ability to degrade the quite intractable polymer chitin, for which it produces three chitinase enzymes ChiA, ChiB, ChiC and a chitin-binding protein Cbp21, which hydrolyse the ß-1,4 link in the chitin chain and promote binding of chitinase to the chitin substrate respectively. These chitinolytic enzymes are utilised by S. marcescens for both basic physiology and also in pathogenesis. In this work, genetic, biochemical and proteomic approaches identified, for the first time, genes that are essential for the secretion of all three chitinases as well as Cbp21. A genetic screen identified genes encoding a holin-like membrane protein (ChiW) and a putative L-alanyl-D-glutamate endopeptidase (ChiX). Subsequent quantitative proteomics experiments and biochemical analyses established that ChiW and ChiX were required for secretion of the entire chitinolytic machinery. Chitinase secretion was observed to be blocked at a late stage in the mutant strains as normally secreted enzymes were found to accumulate in the periplasm, thus implicating ChiW and ChiX in a novel outer membrane protein translocation process. It is proposed that the bacterial genome-encoded holin-like protein and endopeptidase identified represent a putative secretion system utilised by Gram-negative bacteria. In addition to this, genes encoding the chitinolytic machinery and the putative secretion apparatus were shown to be bimodally regulated and co-ordinately expressed.
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Moya, Torres Aniel. "The role of Serratia marcescens OmpF and OmpC porins in antibiotic resistance and virulence." Microbiology, 2014. http://hdl.handle.net/1993/30388.
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Serratia marcescens is a microorganism that constitutes one of the primary causes of nosocomial outbreaks in hospitals. One characteristic of S. marcescens clinical isolates is the high resistance to antimicrobials used in the clinic. Recent reports have attributed antibiotic resistance to altered porin expression. In this study, S. marcescens Db11 isogenic porin mutants were generated using the generalized transducing phage IF3 to move marked target-genes between isogenic strain backgrounds, prior to removal of the antibiotic resistance cassette by Flp-FRT strategy. Mutants for three classical porins were obtained and the effect of ompF and ompC deletion on antimicrobial resistance was evaluated by MIC. The use of this method avoided the incorporation of additional resistance markers and is an alternative strategy to create clean unmarked Serratia mutant strains. The lack of OmpF, but not OmpC, significantly increased MIC values to the β-lactam drugs such as ampicillin and cefoxitin as well as to nitrofurantoin. Genetic deletion of both ompF and ompC did not compromise the integrity of the bacterial cell envelope in optimal growth conditions, suggesting that other outer-membrane porins may function in a compensatory role to facilitate nutrient uptake and cell envelope integrity. S. marcescens is a pathogen of C. elegans and can be used to study host response to bacterial infections. The host model Caenorhabditis elegans was used in this study to investigate if porin deficits affected bacterial virulence. When porin mutants were evaluated in the C. elegans host model, the virulence of the single porin mutant strains increased in comparison to the wild-type. This study demonstrated that mutations of ompF and ompC did not attenuate S. marcescens virulence, but rather demonstrated a hypervirulent phenotype when they were assessed in C. elegans. The absence of OmpF and OmpC porins in S. marcescens appeared to increase the bacterial invasion of C. elegans nematode tissue. Further studies are required to fully investigate the hypervirulent phenotype of these mutant strains. This study reveals that decrease of outer membrane permeability due to porin mutation alters antimicrobial resistance and does not generate virulence attenuation in S. marcescens Db11.May 2015
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Escobar, Marcelo Martins. "Atividade citotoxica do sobrenadante de cultura de Serratia marcescens fitopatogenica." [s.n.], 2002. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317315.
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Orientadores : Tomomasa Yano, Gleize Villela CarbonellDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Mestrado
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Berlanga, Herranz Mercedes. "Mecanismos de resistencia a las quinolonas en Serratia marcescens." Doctoral thesis, Universitat de Barcelona, 1999. http://hdl.handle.net/10803/672847.
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Esta tesis doctoral forma parte de un conjunto de trabajos desarrollados por el grupo de investigación del Dr. M. Viñas del Departamento de Microbiología y Parasitología Sanitarias de Ia Division de Ciencias de Ia Salud de la Universidad de Barcelona.
La mayoría de los trabajos publicados hacen referenda a especies como Escherichia coli, Pseudomonas aeruginosa o Staphylococcus aureus, pero en Serratia marcescens los mecanismos de resistencia han sido poco estudiados. Sin embargo S. marcescens ha producido durante los ultimos afws un inusual elevado número de episodios infecciosos en los centros hospitalarios españoles, además estudios epidemiológicos han constatado un elevado porcentaje de aislados resistentes a las fluoroquinolonas en Serratia y Enterobacter, que es superior a cualquier otro género de las enterobacteriáceas.
El objetivo principal de esta tesis ha sido Ia de aportar más conocimientos en el estudio de los mecanismos de resistencia a l as quinolonas en S. marcescens.
Los objetivos concretes de la presente tesis doctoral son:
1. La obtención y caracterización de mutantes espontáneos resistentes at ciprofloxacino obtenidos in vitro.
2. Investigar la importancia de la membrana externa (papel del lipopolisacarido y porinas) y las características fisicoquímicas de las quinolonas (hidrofobicidad y grado de protonacion en funcion del pH externo) en la acumulación de estos antibióticos por Ia bacteria S. marcescens.
3. Comprobar si existen variaciones en la acumulación del ciprofloxacino,debido a Ia competencia por la vía de entrada, incubando este antibiótico simultanéamente con otros agentes antibacterianos que pasan a través de las porinas.
4. La busqueda y caracterización de bombas de reflujo en Serratia marcescens, ya que una baja permeabilidad no podría explicar por sí sola niveles significativos de resistencia clínica, de tal manera que sería/n necesario/s otro/s mecanismo/s que actuaran de forma sinérgica. Se cree que este segundo factor podría ser el reflujo o extrusión de substancias.
5. Estudiar el mecanismo de acción antibacteriano del ciprofloxacino y ácido nalídxico en S. marcescens.
6. Estudiar las variaciones de la susceptibilidad y acumulación de quinolonas en presencia de analgésicos (ácido salicílico y paracetamol).
7. El estudio comparativo de Ia acumulación y susceptibilidad de los derivados del ciprofloxacino en S. marcescens.
8. Comparar Ia acumulación y susceptibilidad del ciprofloxacino en S. marcescens, Escherichia coli, Pseudomonas aeru9inosa y Staphylococcus aureus.
9. Comprobar si existe alguna mutación en la región QRDR (quinolone resistance determining region) comprendida entre los residuos ala-67 y gln -106 de la subunidad A de la DNA girasa, ya que algunas mutaciones puntuales en GyrA de la DNA-girasa causan elevada resistencia.
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Labbate, Maurizio Biotechnology & Biomolecular Sciences Faculty of Science UNSW. "N-acylhomoserine lactone regulation of adhesion and biofilm differentiation in Serratia marcescens MG1." Awarded by:University of New South Wales. Biotechnology and Biomolecular Sciences, 2004. http://handle.unsw.edu.au/1959.4/20461.
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Serratia marcescens is an opportunistic pathogen involved in predominantly nosocomial infections, however, it is also implicated as a common cause of microbial keratitis. Since many S. marcecens strains are also resistant to multiple antibiotics, this organism represents a growing public health problem. S. marcescens MG1 utilises a regulatory system for regulation of swarming motility and exo-enzyme secretion that relies on the production of a diffusible signal identified as N-butanoyl-L-homoserine lactone (C4-HSL). The aim of this study was to determine the role of C4-HSL in surface colonisation (adhesion and biofilm formation). In this thesis, the development of a novel biofilm in S. marcescens MG1 is described. The biofilm comprises of an intricate and complex structure consisting of long filamentous cells, cell aggregates and cell chains. Two C4-HSL controlled genes (bsmA and bsmB) are shown to be crucial for biofilm formation. It is proposed that C4-HSL regulated bsmA and bsmB gene products are engaged in fine tuning aggregation at a specific time point in late biofilm development. Since adhesion is the first stage of colonisation, the role of C4-HSL in adhesion to a hydrophilic abiotic surface (HAS) and a human corneal epithelial (HCE) cell line was assessed. While adhesion to the HAS was found to be C4-HSL controlled, this was not the case for adhesion to the HCE cells. In adhesion to the HAS, mutations in the following C4-HSL regulated genes resulted in reduced adhesion; a sensor kinase gene (rssA), a type I transporter gene (lipB), bsmA and bsmB. These four genes were found to effect the expression of type I fimbriae which is proposed to be the adhesin affecting C4-HSL regulated adhesion. While C4-HSL is not involved in adhesion to the HCE cell line, the genes bsmA and bsmB are important. It is proposed that bsmA and bsmB dependent HCE adhesion is due to the requirement of these genes for type I fimbriae production. Furthermore, C4-HSL was found to regulate capsule polysaccharide and OmpX production and repress cytotoxic activity against HCE cells and erythrocytes. It is proposed that cytotoxicity is mediated by ShlA haemolysin.
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RODRÍGUEZ, Dayana Montero. "Potencial biotecnológico de Serratia marcescens UCP/WFCC 1549 na degradação de combustíveis, na produção de lipídeos e de biossurfactante." UNIVERSIDADE FEDERAL DE PERNAMBUCO, 2015. https://repositorio.ufpe.br/handle/123456789/15335.
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CNPQ
Serratia marcescens UCP/WFCC 1549, isolada do solo do semi-árido do Estado de Pernambuco - Brasil, foi investigada quanto o seu potencial de biodegradação de combustíveis, como também na produção de lipídeos e biossurfactante. A degradação de combustíveis foi avaliada utilizando o meio basal Bushnell Hass (BH), o indicador redox 2,6- diclorofenol – indofenol e a cepa de S. marcescens selvagem e aclimatada em diferentes concentrações do óleo diesel (2, 4, 6, 8, 10, 12 e 15%). Os resultados obtidos demonstraram que a bactéria aclimatada a 15% do óleo diesel apresentou os melhores índices de degradação, com valores de 79,63% para o biodiesel de algodão, 65,57% para o biodiesel de girassol, 60,50% para o diesel, 57,20% para gasolina e 39,26% para querosene. Além disso, S. marcescens demonstrou propriedade de crescer e acumular lipídeos (> 40%) utilizando resíduos agro-industriais (manipueira e óleos vegetais pós-fritura). Os lipídeos produzidos mostraram perfis de ácidos graxos com maior porcentagem em ácidos graxos monoinsaturados, sugerindo uma composição que corresponde às características requeridas para o biodiesel. Ao mesmo tempo, S. marcescens demonstrou habilidade para converter resíduos agroindustriais (manipueira e óleo de milho pós-fritura) em associação com lactose, na produção de biossurfactante, empregando um planejamento fatorial 23. A seleção da melhor condição do planejamento foi avaliada pela variável resposta tensão superficial. O melhor resultado foi obtido no meio constituido por 6% de manipueira e 7,5% de óleo de milho pós-fritura, na ausência de lactose, com uma redução da tensão superficial da água de 72 para 26,2 mN/m. O biossurfactante produzido apresentou propriedade emulsificante (EI24), com valores superiores a 60% de emulsificação utilizando os óleos de soja, diesel, motor e motor queimado. Adicionalmente, o biossurfactante demonstrou estabilidade na redução da tensão superficial frente a diferentes valores de pH, temperatura e NaCl, e mostrou excelente eficiência na remoção de óleo de motor em água, areia de praia e sedimento de mangue (78%, 88,27% e 73,70%, respectivamente). Portanto, S. marcescens UCP/WFCC 1549 demonstrou seu elevado potencial biotecnológico para a produção de biodiesel de boa qualidade, assim como de biossurfactante com aplicação promissora em processos de biorremediação de ecossistemas contaminados com petróleo e seus derivados.
Serratia marcescens UCP/WFCC 1549, isolated from soil of the semi-arid of state of Pernambuco, Brazil, was investigated with regard to their potential to fuel biodegradation as well as for the production of lipids and biosurfactant. The degradation was assessed using Bushnell Hass (BH) medium, the redox indicator 2,6-dichlorophenol – indophenol and S. marcescens wild-type and acclimatized in different concentrations of diesel (2, 4, 6, 8, 10, 12 and 15%). The obtained results showed that strain acclimatized in 15% diesel oil exhibited the best degradation index (79,63% of cotton biodiesel, 65,57% of sunflower biodiesel, 60,50% of diesel, 57,20% of gasoline and 39,26% of kerosene). Also, S. marcescens demonstrated the ability to grow and accumulate lipids (> 40%) using agro-industrial residues (cassava wastewater and waste vegetable oils). The produced lipids exhibited balanced profiles of fatty acids, mainly monounsaturated fatty acids which correspond with biodiesel requirements. In addition, S. marcescens showed ability to produce biosurfactant by bioconversion of agro-industrial residues (cassava wastewater and corn waste oil), in association with lactose, through a 23 factorial design. The best result was obtained in medium containing 6% cassava wastewater and 7,5% corn waste oil, in absence of lactose, with reduction of surface tension of water from 72 to 26,2 mN/m. The biosurfactant had good properties in the emulsification of hydrophobic compounds (EI24 > 60% of soybean oil, diesel oil, engine oil and burned engine oil). Moreover, the biosurfactant demonstrated stability in a wide range of pH, temperature and salinity. Also, it showed excellent efficiency on dispersion of engine oil in water (78%) as well as removing it in beach sand and mangrove sediment (88,27% and 73,70%, respectively). Then, S. marcescens UCP/WFCC 1549 demonstrated their high biotechnological potential for production of good quality biodiesel, as well as biosurfactant with promising application in bioremediation processes.
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de, Assis Alcoforado Costa Marília. "Secretion and regulation of the chitinolytic machinery in Serratia marcescens." Thesis, University of Dundee, 2017. https://discovery.dundee.ac.uk/en/studentTheses/6ff01f8b-9ea7-4fe8-94c9-180b1bd5172c.
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Protein secretion is an important activity used by bacterial to sense, adapt and survive in different environments. In Gram-negative bacteria proteins destined for secretion must be translocated across both the inner and outer membranes in either a one- or a two-step process. Serratia marcescens is renowned as a prolific secretor of proteins and is one of the most effective microbes at extracellular chitin degradation. To achieve this S. marcescens secretes three chitinases (ChiA, ChiB and ChiC) as well as a chitin binding protein (CBP21) that together with the periplasmic chitobiase (Chb) form the chitinolytic machinery. Research in this group had identified two genes (chiW and chiX) encoding a holin-like protein and a putative endopeptidase, that are essential for secretion of the chitinolytic machinery. Moreover chiA was found expressed by a small subpopulation of cells and in coordination with chiX. This project used fluorescence microscopy experiments to show the co-expression of chiX with chiC alongside chitinase secretion assays that provided initial insights regarding the role of protein terminus on chitinase stability and secretion. This project also investigated the role of ChiR, a LysR-type transcriptional regulator, and Hfq, a RNA-binding protein, on Serratia chitinolytic machinery. Results revealed that Hfq plays a role on ChiR synthesis which modulates chitinase and chiWX transcription. In addition, overexpression of chiR resulted in a higher population of ChiC producer cells and further investigations revealed a plethora of ChiR target genes and binding motifs.
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Cristina, Lapenda Lins Jeanne. "Produção e caracterização de prodigiosina isolada de Serratia marcescens UCP 1549." Universidade Federal de Pernambuco, 2010. https://repositorio.ufpe.br/handle/123456789/1725.
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Previous issue date: 2010Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Prodigiosinas é uma família de pigmentos naturais, de cor vermelha caracterizado por um esqueleto comum pirrolilpirrometano, produzido por várias bactérias, porém primeiro produzido por Serratia marcescens. Este pigmento é uma droga promissora, devido às suas características de atividade antifúngica, imunossupressores e antiproliferativa. As condições ótimas para o aumento do crescimento em S. marcescens está relacionada ao aumento da produção do pigmento, sob o ponto de vista industrial. Neste trabalho, foram utilizados os meios convencionais Peptona glicerol e Manitol, bem como os meios alternativos, Caldo de arroz, de gergelim e de amendoim, visando à produção de prodigiosina pela bactéria isolada do solo semi-árido, Serratia marcescens UCP 1549, utilizando fermentação em estado sólido, a 280 C, durante 48 horas de cultivo. A produção da prodigiosina foi observada nos meios convencionais, principalmente meio Manitol, sendo obtidos 1,2g/g de biomassa, porém não foi detectada nos meios alternativos. O pigmento foi purificado por cromatografia de exclusão, empregando-se Sephadex LH-20, obtendo-se 96 frações que foram reunidas, sendo caracterizada por espectrofotometria e espectrometria de massa (GC-MS), sendo sugerido ser Undecilprodigiosina. Estudos foram realizados com a atividade citotóxica para Artemia salina demonstrando uma CL50 de 78,33μg/mL. A fitoxidade para sementes de alface (Lactuca sativa) e pimentão (Capsicum annuum) com inibição da germinação das sementes a partir de concentrações superiores a 40μg/mL, representando mais de 50% de inibição. Os resultados obtidos sugerem alto potencial biotecnológico na produção de Undecilprodigiosina pela nova linhagem de S. marcescens UCP 1549, como também indica como promissores os resultados com o meio Manitol em estado sólido, os processos de extração e purificação do pigmento
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Melo, Patricia da Silva. "Pigmentos obtidos de Chromobacteriun violaceum e Serratia marcescens, propriedade tripanocida da prodigiosina e estudos toxicologicos." [s.n.], 1996. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314599.
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Orientador: Nora Marcela Haun QuirosDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Chromobacterium violaceum é um microrganismo de larga distribuição podendo ser encontrado no solo, água e no Rio Negro (Amazônia). Esta bactéria Gram negativa produz um pigmento denominado violaceína, que apresenta alguma atividade tripanocida. Como a violaceína é produzida em pequena quantidade o propósito inicial desse estudo foi investigar cepas diferentes provenientes do Rio Negro que produzissem a violaceína em um maior rendimento. Um sedimento coletado do Rio Negro foi inoculado em caldo simples, 30°C/24 h e posteriormente inoculado através de estrias em ágar nutriente. Somente três tipos de colônias - branca, amarela e vermelha cresceram (todas bactérias Gram negativas). Após dois dias de incubação a colônia branca adquiriu tonalidade violeta indicando a produção de violaceína. Análises espectrais, UV/Vis, IV (Infra Vermelho) e RMN (Ressonância Magnética Nuclear), confirmaram a presença da violaceína. Para determinar as características de C. violaceum e sua variante não pigmentada, testes laboratoriais foram realizados. A coloração pelo Gram, motilidade e estudos bioquímicos e de crescimento indicaram que as colônias branca/violeta e amarela eram C. violaceum. A colônia vermelha era Serratia marcescens (Chromobacterium prodigiosum) a qual produz o pigmento com ação antibiótica chamado prodigiosina. Os dados espectrais (UV/Vis, IV e RMN) reforçam essa conclusão. O pequeno número de bactérias isoladas na amostra confirma a alta atividade antibiótica dos pigmentos produzidos pela C. violaceum (violaceína) e S. marcescens (prodigiosina) na água do Rio Negro. A quimioterapia da doença de Chagas permanece um problema sem solução, e a pesquisa para drogas alternativas está em andamento. A terapia atual dessa doença é insatisfatória e somente o Nifurtimox está em uso, com diversas restrições na administração em pacientes crônicos, devido aos seus efeitos colaterais. Desse modo é de importância fundamental a pesquisa de novas drogas com mecanismos de ação diferentes do Nifurtimox com o objetivo de evitar esses problemas. A violaceína e a prodigiosina extraída da C. violaceum e da S. marcescens, respectivamente apresentam atividade tripanocida, a primeira possui um ID50. de 46 mM e a segunda, menos que 100 mM. A avaliação da titotoxicidade foi realizada através da inibição da síntese de DNA, redução do MTT e captação do Vermelho Neutro (VN), utilizada em células de hamster chinês V-79 (M8). No teste de viabilidade através da redução do MTT o ID50 foi de 6 mM para a prodigiosina, 7mM para a violaceína e 500 mM para o Nifurtimox, no teste do VN o ID50 para a prodigiosina foi de 1,0 mM, 12 mM para a violaceína e 250 mM para o Nifurtimox. A prodigiosina resultou em um valor de ID50 de 20 mM, o Nifurtimox de 100 mM e a violaceína de 5 mM obtidos através da inibição da síntese de DNA
Abstract: Chromobacterium violaceum is a widely distributed microorganism. It is in soil, water and in the Rio Negro (Amazon). This Gram negative rod shaped bacteria produces the pigment violacein, which has shown trypanocide activity. Since violacein is produced in small quantity, the inicial purpose of this study was to investigate differents strains of bacteria from Rio Negro which may produce violacein in highest yield. Sediment was collected from Rio Negro, inoculated in simple broth, 30°C /24 h and striated in simple agar. Only three kinds of colonies - white, yellow, and red grew (rod Gram negative bacteria). After two days the white strain changed to violet indicating violacein production. Spectral analysis, UV/Vis (UV/Visible), IR (Infra Red) and NMR (Nuclear Ressonance Magnetic), confirmed the presence of violacein. In order to determine of C. violaceum characteristics and its non pigmented variants, laboratories tests were undertaken. Gram'stainning, motility, morphological, growth and biochemical studies indicated that the white, yellow and violet colonies were C. Violaceum. The red one was Serratia marcescens (Chromobacterium prodigiosum) which produces the red pigment antibiotic prodigiosin. The spectral data (UV/Vis, IR and NMR) reinforce this conclusion. The low number of microorganisms isolated in the sample confirm the high antibiotic activity of the pigments produced by C. Violaceum (violacein) and Serratia marcescens (prodigiosin) in the Rio Negro water. The chemotherapy of Chagas' disease remains an unsolved problem, and the search for alternative drugs is in course. Current therapy of this disease is unsatisfactory and only Nifurtimox is in general used, with several restricted applicability for chronic patients, as well being deleterious effects. Thus, it is of fundamental importance to search for new drugs with different mechanism of action of Nifurtimox in order to avoid these problems. We have found a potential compounds for the treatment of Chagas' disease, the pigments extracted from S. marcescens and C. violaceum, respectively prodigiosin (ID50 of less 100 mM) and violacein (ID50 of 46 mM). Evaluation ID50 through DNA synthesis inhibition, soluble tetrazolium/formazan (MTT) and Neutral Red (NR) tests on V-79 Chinese hamster (M-8) cells were carried out. Using MTT viability test, ID50 was 6 mM for prodigiosin, 7 mM for violacein and 500 mM for Nifurtimox, and for NR test the ID50 was 1.0 mM, 12 mM and 250 mM for prodigiosin, violacein and Nifurtimox, respectively. Prodigiosin resulted in a ID50 value of 20 mM, for violacein of 5 mM and for Nifurtimox of 300 mM obtained through DNA synthesis inhibition
Mestrado
Bioquimica
Mestre em Ciências Biológicas
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Kurz, Cyril Léopold. "Génétique moléculaire de l'interaction entre le nématode Caenorhabditis elegans et la bactérie Serratia marcescens." Aix-Marseille 2, 2003. http://www.theses.fr/2003AIX22040.
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Malki, Idir. "Etude structurale et fonctionnelle de la protéine HasS, un facteur anti-sigma impliqué dans la régulation de l'acquisition de l'hème chez Serratia marcescens." Paris 6, 2013. http://www.theses.fr/2013PA066248.
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Chez les bactéries Gram-négatif, les systèmes d’acquisition des différentes sources de fer sont généralement soumis à une régulation très fine. Ils sont régulés en fonction de la concentration intracellulaire en fer. Pour certains, il existe un niveau de régulation supplémentaire qui s’effectue par une signalisation transmembranaire. Cette signalisation nécessite l’interactions entre trois protéines spécifiques d’un système donné : le récepteur membranaire et le facteur sigma de type ECF (extracytoplasmic fonction) et son anti-sigma qui une protéine de membrane interne. Les mécanismes moléculaires de ce processus de signalisation sont inconnus. Durant cette étude, nous nous sommes intéressés à la voie de signalisation régulant l’acquisition de l’hème via le système Has (heme acquisistion system) de Serratia marcescens. Nous nous sommes focalisés sur la première étape de cette signalisation transmembranaire à savoir, l’interaction entre le domaine périplasmique du récepteur HasR et le facteur anti-sigma HasS. Nous avons étudié les aspects structuraux et fonctionnels de ces deux protéines. Nous avons déterminé par RMN la structure 3D du domaine périplasmique de HasR et identifié les résidus impliqués dans la voie de signalisation. De plus, nous avons produit pour la première fois le domaine périplasmique de HasS. Nous avons ensuite déterminé son état de repliement et étudié son interaction avec le domaine périplasmique de HasRIron uptake systems in gram-negative bacteria are generally tightly regulated by iron intracellular concentration. Some of them are also controlled by a transmembrane signaling. Three specific proteins are involved in the latter process : the outer membrane receptor and the ECF (extracytoplasmic function) sigma and antisigma factors. The data about these proteins and of their molecular interactions are sparse and the mechanisms governing this transmembrane signalisation are not understood. We present here the results of the study of the transmembrane signaling in the Has system (heme acquisition system) of Serratia marcescens. We focused on the interaction between the periplasmic domain of the receptor HasR and the ECF anti-sigma factor HasS, two proteins controlling the first step of this signaling process. We carried out structural and functional studies of these protiens. We solved the structure of the periplasmic domain of HasR by NMR and determined which of its residues were involved in the transmembrane signaling. We produced, for the fisrt time, the periplasmic domain of HasS and carried out its characterized regarding its structural features and its interaction with the periplasmic domain of HasR
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Harris, A. K. P. "Analysis of quorum sensing and prodigiosin biosynthetic genes in Serratia marcescens." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603740.
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Serratia marcescens 274 contains a prodigiosin biosynthetic gene cluster, termed the pig cluster. The pig cluster contains 14 pig genes, pigA to N that were cloned on the cosmid pPIG4. The pPIG4 cosmid was able to direct the synthesis of prodigiosin in Escherichia coli. This is the first example of reconstitution of prodigiosin synthesis in this host. pPIG4 also encoded production of pigment in a biosynthetic mutant of Serratia sp. 39006, though not in Erwinia carotovora subsp. carotovora. The pigments from Serratia sp. 39006 and S. marcescens 274 were purified and analysed using ES-MS. The pig genes, pigA to N, were sequenced, as were the genes flanking the cluster: cueR 5’ of pigA and copA 3’ of pigN. The pig gene cluster is arranged similarly to the Serratia sp. 39006 pig cluster, with pigABCDEFGHJKLMN all in one direction of transcription, suggesting an operon. Two striking differences between the Serratia sp. 39006 and the S. marcescens 274 pig clusters are that (1) the Serratia sp. 39006 pig cluster contains an extra gene, pigO, the product of which shows low similarity to a VirR related protein and (2) the S. marcescens 274 pig cluster is flanked by cueR and copA homologues. These genes, which encode a regulator and a copper transporter respectively, are typically adjacent and divergently transcribed in other bacteria. The Serratia sp. 39006 and S. marcescens 274 pig genes encode proteins that are from 52 to 85% similar to each other. The pig genes also show similarity to genes found in the red cluster of Streptomyces coelicolor. The red cluster encodes 23 proteins that direct the synthesis of undecylprodigiosin. At least 12 of the red genes have homologues among the pig genes. Red and Pig homologues share between 23 to 43% similarity with each other. The order and orientation of the red genes compared to the pig genes is completely different, indicating gene rearrangement if these two clusters arose by divergent evolution.
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Stead, Paul. "Carbapenem antibiotic biosynthesis and regulation in Erwinia carotovora and Serratia marcescens." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315159.
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Gerc, Amy. "Analysis of the diverse antibacterial strategies used by Serratia marcescens Db10." Thesis, University of Dundee, 2014. https://discovery.dundee.ac.uk/en/studentTheses/823bcdd0-8706-4d2a-b94c-23f46277bde6.
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Cescau, Sandra. "Sécrétion de l'hémophore HasA de Serratia marcescens via un transporteur ABC." Paris 7, 2007. http://www.theses.fr/2007PA077213.
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Chez les bactéries à Gram négatif, la voie de sécrétion ABC (T1SS) permet l'export de protéines présentant un signal de sécrétion C-terminal non clivable. Les transporteurs sont constitués de 3 protéines membranaires : une ATPase de la famille largement répandue des protéines ABC, une deuxième protéine de membrane interne et une protéine de membrane externe de la famille de TolC. TolC participe également aux pompes d'efflux de détergents et d'antibiotiques, les T1SS et les pompes d'efflux co-exprimés se partageant TolC sans perte de fonctionnalité. Le complexe de sécrétion n'est pas associé de façon permanente. Sa formation est induite par l'interaction entre le signal de sécrétion et la protéine ABC. L'oligomérisation du transporteur a été étudié par des approches biochimiques : chromatographie d'affinité et pontage chimique. Les mécanismes moléculaires permettant l'association et la dissociation du transporteur sont inconnus. Lors de ces travaux, le T1SS modèle utilisé est celui de l'hémophore HasA de S. Marcescens. Nous avons montré que HasA dépourvu de son signal C-terminal induit une oligomérisation stable du transporteur, séquestrant la protéine TolC. La pénurie de molécules TolC disponibles pour l'association aux pompes d'efflux entraîne une sensibilité accrue au SDS. L'hyperproduction de la protéine TolC réverse le phénotype de sensibilité. L'expression du signal de sécrétion sous forme de polypeptide distinct restaure aussi la résistance montrant que le signal C-terminal est actif de façon intermoléculaire. Ainsi, l'hémophore a deux domaines d'interaction avec la protéine ABC : le signal C- terminal et un 2eme domaine dit domaine d'ancrageThe Type I secretion System makes it possible the Gram negative bacteria to export proteins presenting an uncleaved C-terminal secretion signal. The transporter are constituted of 3 proteins: a membrane ATPase of the large family of ABC proteins, a second cytoplasmic membrane protein and an outer membrane protein belonging to TolC family. TolC is multifunctional. It participates also to efflux pump which expulse detergents and antibiotics. When they are co-expressed, T1SS and efflux pump share TolC without lost of functionality. The secretion complex is not permanently associated. Its formation is induced by the interaction between the secretion signal and the ABC protein. The oligomerisation of the transporter has been studied by several biochemical approaches: affinity chromatography and cross-linking. Th molecular mechanisms of the association-dissociation of the transporter are unknown. During this work, the model studied was the T1SS of the HasA hemophore of S. Marcescens. We have shown that Has deleted for its C-terminal secretion signal induced a stable oligomerisation of the transporter, trapping TolC proteins. The unavailability of TolC molecules for the efflux pump involved a increased SDS sensitivity. The hyperproduction of the TolC protein reversed this phenotype. The expression of the secretion signal as a single molecule also restored the resistance This suggests that the secretion signal is active in an intermolecular manner. Thus, the hemophore presents 2 interaction domains with the ABC protein: the secretion signal and a second site name the anchoring domain
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Parente, Ticiana MonâtAlverne Lopes. "Perfil de resistÃncia a antibiÃticos e a terapia fotodinÃmica antimicrobiana exibida por isolados ambientais, orais e extra-orais de Serratia marcescens." Universidade Federal do CearÃ, 2010. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=5353.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorSerratia marcescens se encontra largamente distribuÃda na natureza, mas tem emergido nos Ãltimos anos como um importante patÃgeno nosocomial resistente a diversos antimicrobianos. Este estudo teve como objetivo verificar a susceptibilidade de isolados ambientais, orais e extra-orais de Serratia marcescens a diferentes antibiÃticos e avaliar a terapia fotodinÃmica antimicrobiana na reduÃÃo do crescimento bacteriano em culturas de cÃlulas planctÃnicas e biofilme. O teste de susceptibilidade antimicrobiano E-test foi realizado para as 55 cepas e o TFA para as 30 cepas mais resistentes aos antimicrobianos testados. O efeito antimicrobiano do azul de o-toluidina associado com 4,72 J cm-2 de luz emitida por um diodo (LED) foi avaliado. Antes e apÃs os tratamentos, os inÃculos bacterianos foram analisados com consideraÃÃo do nÃmero de unidades formadoras de colÃnias. Considerando o perfil antimicrobiano observamos que das 55 cepas analisadas, 13 (23,63%) apresentaram resistÃncia à doxiciclina, mas apenas um (1,81%) isolado apresentou resistÃncia ao ciprofloxacino, outro à tobramicina e outro à cefotaxima; 24 (43,63%) cepas apresentaram sensibilidade intermediÃria à doxiciclina, todas foram sensÃveis ao imipenem e a maioria foi sensÃvel ao ciprofloxacino, à tobramicina e à cefotaxima. A anÃlise estatÃstica demonstrou nÃo haver diferenÃas significativas no perfil de resistÃncia das amostras de diferentes origens em relaÃÃo as drogas DX, CT e IP. Considerando a resistÃncia a CI, as amostras ambientais foram significativamente mais resistentes do que as amostras orais e extra-orais. Para a droga TM, as amostras orais foram significantemente mais sensÃveis do que as demais amostras. A irradiaÃÃo das culturas planctÃnicas e biofilmes na ausÃncia de TBO (L+C-), a incubaÃÃo com TBO sozinho (L-C+) e o grupo controle nÃo tratado (L-C-) nÃo apresentou efeitos significativos na viabilidade das cepas de S. marcescens estudadas (p < 0,05). DecrÃscimos significativos na viabilidade bacteriana foram observados somente quando cultura planctÃnica e biofilme de cepas ambientais, orais e extra-orais de S. marcescens foram expostas ao azul de orto toluidina e luz LED ao mesmo tempo (L+C+). ReduÃÃes significativas nas contagens bacterianas foram observadas pela Terapia FotodinÃmica Antimicrobiana com variaÃÃo de 10-11 a 10-7. A associaÃÃo de TBO e LED, com densidade de energia de 4,72 J cm-2 , foi efetivo na reduÃÃo da viabilidade bacteriana em cepas ambientais, orais e extra-orais de S. marcescens podendo ser uma ferramenta biotecnolÃgica Ãtil no controle da resistÃncia bacteriana.
Serratia marcescens is widely distributed in nature, but has emerged in the last years as important nosocomial pathogen with resistance of many antimicrobial drugs. This study aimed to verify the susceptibility of Serratia marcescens isolates from environment, from oral infections and from extra-oral infections to different antibiotics and evaluate the antimicrobial effect of photodynamic antimicrobial therapy as biotechnology tools reducing bacterial growth in planktonic cells and biofilm. E-test were performed for fifty-five strains and the PACT for the thirty strains more resistant to antimicrobials tested. The antimicrobial effect of toluidine blue O, associated with 4,72 J cm-2 of a light-emitting diode , was evaluated. Before and after the treatments, bacterial inocula were analysed with regard to the number of colony- forming units. For antimicrobials, we observed that the 55 strains analyzed, 13 (23.63%) were resistant to doxycycline, but only one (1.81%) isolate showed resistance to ciprofloxacin, another to tobramycin and another to cefotaxime, 24 ( 43.63%) strains had intermediate sensitivity to doxycycline, all were sensitive to imipenem and most were sensitive to ciprofloxacin, tobramycin and cefotaxime Statistical analysis showed no significant differences in resistance of samples of different origins for drugs DX, CT, and IP. Considering the resistance to CI, the environmental samples were significantly more resistant than samples oral and extra-oral. For the drug TM, the oral samples were significantly more sensitive than the other samples. The irradiation of planktonic and biofilm cultures in the absence of TBO (L+S-), incubation with TBO alone (L-S+) and untreated control group (L-S-) had no significant effect on the viability of strains of S. marcescens studied (p <0.05). Significant decreases in bacterial viability was observed only when planktonic and biofilm culture of environmental strains, oral and extra-oral S. marcescens were exposed to toluidine blue O and LED light at the same time (L+S+). Significant reductions in bacterial counts were observed by antimicrobial photodynamic therapy ranging from 10-11 to 10-7.The association of TBO and light, with energy density 4,72 J cm-2, was effective in reducing the viability of bacterial strains in environmental, oral and extra-oral S. marcescens and can be a useful biotechnological tool in the control of bacterial resistance.
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Coderch, Marco Nuria. "Estudi estructural i genètic del nucli del lipopolisacàrid de "Serratia marcescens" N28b." Doctoral thesis, Universitat de Barcelona, 2008. http://hdl.handle.net/10803/2423.
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Serratia marcescens és un bacteri gramnegatiu que es comporta com un patogen oportunista i és responsable d'un nombre creixent d'infeccions nosocomials. Les infeccions més comuns causades per aquest bacteri són pneumònies, infeccions del tracte urinari, septicèmies i meningitis.A la membrana externa de la paret dels bacteris gramnegatius s'hi localitzen unes molècules amfifíliques, anomenades lipopolisacàrids, que consten de tres regions principals: el lípid A, que constitueix la part lipídica, i el nucli i l'antigen O, que formen la part polisacarídica, que es projecta cap a l'exterior. Aquesta particular disposició comporta que el LPS sigui l'antigen superficial més important en els bacteris gramnegatius i un dels principals factors de virulència. Per aquest motiu, ens els últims anys s'han estudiat les estructures químiques i les funcions dels LPSs d'un nombre important de bacteris gramnegatius, així com també els responsables genètics de la seva biosíntesi. Aquesta tesi s'ha centrat en l'estudi estructural i genètic del nucli del LPS de S. marcescens N28b O4.
Anàlisis químiques i estructurals realitzades sobre l'oligosacàrid majoritari de la regió del nucli del LPS d'un mutant de S. marcescens N28b deficient en antigen O juntament amb anàlisis de complementació ens van permetre proposar la següent estructura química: β-Glc-(1→6)-α-Glc-(1→4)-α-D-GlcN-(1→4)-α-D-GalA-[(2←1)-α-D,D-Hep-(2←1)-α-Hep]-(1→3)-α-L,D-Hep[(7←1)-α-L,D-Hep]-(1→3)-α-L,D-Hep-[(4←1)-β-D-Glc]-(1→5)-Kdo. La configuració D dels residus de β-Glc, α-GlcN, i α-GalA es va deduir a partir de les dades genètiques i per això s'ha de considerar temptativa. Diversos anàlisis comparatius realitzats sobre la regió del nucli del LPS de la soca salvatge i del mutant deficient en antigen O van demostrar que aquesta regió és compartida per ambdós bacteris i per tant l'estructura de nucli proposada és perfectament extrapolable a la de la soca salvatge S. marcescens N28b. A més, per espectrometria de masses de ressonància d'ió ciclotró per transformada de Fourier i ionització per electrosprai (ESI FT-ICR-MS) es van identificar altres oligosacàrids en aquesta regió que probablement contenien substitucions addicionals per residus de D-glicero-D-talo-oct-2-ulosonic (Ko) o d'àcid hexosurònic, que hi eren presents tant a la regió del nucli de la soca salvatge com del mutant deficient en antigen O. D'altra banda la identificació de diferents ions que diferien uns dels altres per masses de +80 Da, suggeriren la presència de substitucions no-estequiomètriques per residus monofosfats.
La identificació de l'estructura del nucli del LPS de S. marcescens N28b va permetre poder completar, en la segona part del treball, la caracterització funcional dels gens de l'agrupació waa d'aquesta soca bacteriana, implicada en la biosíntesi del nucli del seu LPS. Estudis previs realitzats sobre aquesta agrupació, constituïda per 14 pautes de lectura oberta, havien permès identificar la funció dels gens compartits amb la resta d'enterobacteris. La caracterització de la resta de gens no compartits es va realitzar a partir d'anàlisis químics i de complementació gènica sobre mutants no polars en aquests gens obtinguts en aquest treball. D'aquesta manera, l'estudi de les estructures de nucli incomplert d'aquests mutants o dels canvis fenotípics que es produïen com a conseqüència de la mutació en comparació amb la soca salvatge van permetre proposar funcions per la resta de gens de l'agrupació waa de S. marcescens N28b. Com a més rellevant, es pot citar la identificació dels gens responsables de la transferència del disacàrid lateral d'heptosa, dels residus d'àcid galacturònic i glucosamina i dels tres residus de glucosa.
Genetic and Structural Study of the Core Region of the Lipopolysaccharide from Serratia marcescens N28b"
"Serratia marcescens" is a recognised nosocomial gram-negative pathogen that mainly causes pneumonia, septicaemia, meningitis and urinary tract infections.
In gram-negative bacteria, the lipopolysaccharide (LPS) is one of the major structural and immunodominant molecules of the outer membrane. It consists of three domains: lipid A, core oligosaccharide and O-antigen. Lipopolysaccharides are important virulence factors in pathogenic strains. Thus, structures and functions of lipopolysaccharides from many gram-negative bacteria as well as the genetic determinants of their biosynthesis have been intensely investigated. This doctoral thesis has focused in the structural and genetic characterisation of the LPS core region of S. marcescens N28b.
Chemical and structural analyses of the major oligosaccharide from the LPS core region of an O-antigen-deficient mutant of S. marcescens N28b as well as complementation analyses led to the following proposed structure: β-Glc-(1→6)-α-Glc-(1→4)-α-D-GlcN-(1→4)-α-D-GalA-[(2←1)-α-D,D-Hep-(2←1)-α-Hep]-(1→3)-α-L,D-Hep[(7←1)-α-L,D-Hep]-(1→3)-α-L,D-Hep-[(4←1)-β-D-Glc]-(1→5)-Kdo. The D configuration of the β- Glc, α-GlcN and, α-GalA was deduced from genetic data and thus is tentative. Several comparative chemical analyses demonstrated that the wild strain S. marcescens N28b and the O-antigen-deficient mutant share the same core region and therefore the proposed core structure is completely applicable to that of the wild strain. Furthermore, other oligosaccharides were identified by ion cyclotron resonance-Fourier-transformed electrospray ionisation mass spectrometry, which presumably contained additional residues of D-glycero-D-talo-oct-2-ulosonic acid (Ko) or of hexuronic acid. Several ions were identified that differed from others by a mass of +80 Da, suggesting a nonstoichiometric substitution by a monophosphate residue.
The elucidation of the structure shown above, allowed us to complete the functional characterisation of the genes in the S. marcescens N28 waa gene cluster involved in the biosynthesis of its LPS core region. Previous studies had led to the identification of waa genes shared by all known "Enterobacteriaceae". Chemical and/ or complementation analyses of several nonpolar mutants within the S. marcescens gene cluster generated in this work allowed us to propose functions for the remaining waa genes. Among others, genes involved in the transfer of the galacturonic acid, glucosamine and the tree glucose residues of the core region as well as in the transfer of the branched heptose disaccharide were identified.
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Owen, Richard A. "Investigating the key components of the chitinase secretion system in Serratia marcescens." Thesis, University of Dundee, 2016. https://discovery.dundee.ac.uk/en/studentTheses/2f3ef294-9a5a-4ece-b286-860758c47079.
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The opportunistic bacterial pathogen Serratia marcescens secretes a ‘chitinolytic machinery’ comprising ChiA, ChiB, ChiC, and Cbp21, that is essential for the efficient utilisation of the extracellular polysaccharide chitin. Secretion of these proteins appears to be a two-step process in S. marcescens with initial export to the bacterial periplasm being followed by a final secretion step across the outer membrane. Successful secretion of the chitinolytic machinery ultimately depends on the products of a four-gene operon, chiWXYZ, which resembles a phage lysis cassette. At the outset of this project the structure, function and interrelationships between the ChiWXYZ proteins was largely unknown and thus a major aim of this work was to provide mechanistic insight into this system. This project therefore details the characterisation of key molecular events in the secretion process. The chiW and chiX genes encode putative holin and endolysin proteins, respectively, and these are essential for secretion of chitinases. Using X-ray crystallography, the structure of full-length ChiX was resolved to 1.34 Å, revealing structural similarities to the lysostaphin-type (LAS) family of peptidases. Purified ChiX was shown to possess L-Ala D-Glu endopeptidase activity, establishing the peptidoglycan cross-link in the periplasm as its substrate. ChiX has no obvious signal peptide, however experiments outlined here provided evidence that the holin ChiW was responsible for ChiX passage to the periplasm. Finally, proteomic data sets for strains overproducing a central regulator of the system, ChiR, were analysed in an attempt to discover hitherto unknown components or substrates of the chitinase secretion machinery.
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Piqué, i. Clusella Núria. "Caracterització genètica i química del nucli del LPS de Serratia marcescens N28b." Doctoral thesis, Universitat de Barcelona, 2000. http://hdl.handle.net/10803/673123.
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Los genes implicados en la biosíntesis del núcleo del Lipopsolisacárido
(LPS)- llamados genes naa-fueron caracterizados en Serratia mascescens
N28b.
Los genes naa caracterizados constituyen una agrupación genética característica
que se describe por primera vez. Los genes que se caracterizaron fueron:
AmmaF, maaQII,maaG, maaB, maaQ, maaA, maaE i edtB.
A diferenciar del custer maa de Escherichia coli o Salonmella enterica,
en Smarcescens destaca la presencia del gen maaE.
El estudio de la función de este gen demostró que podría codificar para
una glucosil transferesa. Se observó que la proteina maaE en un LPS con
estructura Bdi oRc de Eicoli o Senterib, podía transferir un residuo de
blc a nivel de la HepI del núcleo interno mediante un enlace Beta (1-4).
Este residuo de blc se encuentra también en el núcleo de S. Morcescens
según estudios realizados en el LPS de S.morceslens N28b.
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Cwerman-Thibault, Hélène. "Mécanisme moléculaire de l'induction de l'expression de l'opéron has de Serratia marcescens." Paris 7, 2007. http://www.theses.fr/2007PA077116.
Full textAbstract:
Le système Has de Serratia marcescens est un système d'acquisition de Thème particulièrement efficace grâce à la sécrétion d'une petite protéine de forte affinité pour Thème appelée hémophore qui capte Thème extracellulaire et le retourne au récepteur de membrane externe HasR. L'expression de ce système est soumise à la régulation pléiotrope négative médiée par la protéine Fur liée au fer et à une régulation positive spécifique par une cascade de signalisation. Cette cascade est composée de trois éléments : le récepteur de membrane externe HasR et les protéines Hasi et HasS qui sont respectivement un facteur sigma ECF et un facteur anti-sigma. La cascade de signalisation est induite par la fixation de Tholo-hémophore (chargé en hème) sur le récepteur HasR mais ni par Thème ni par Tapo-hémophore (non chargé en hème) qui se fixent aussi sur le récepteur HasR. Le stimulus qui permet le déclenchement de la cascade de signalisation a été dissocié en deux éléments nécessaires pour l'induction : l'atterrissage de Thème sur le récepteur HasR et la présence de la région 50-55 de Thémophore HasA localisée dans une des deux régions d'interaction de Thémophore avec le récepteur. Ni le transport de Thème par le récepteur HasR, ni le recyclage de Thémophore déchargé de son hème ne semblent nécessaires pour le déclenchement de la cascade de signalisation du système Has. La régulation de l'expression des gènes hasl et hasS a aussi été étudiée et nous avons mis en évidence un nouveau mode de régulation pour des facteurs sigma et anti-sigma dans lequel le facteur sigma Hasi régule positivement l'expression du facteur anti-sigma HasSThe Serratia marcescens Has System is a heme acquisition system particularly effective due to the secretion of a small protein named the hemophore which has a high affinity for heme, scavenge the extracellular heme and return it to the outer membrane receptor HasR. The expression of this System is submitted to the negative pleiotropic régulation mediated by the Fur protein charged with iron and to a positive specific regulation by a signaling cascade. This signaling cascade is composed of three elements: the outer membrane receptor HasR and the Hasi and HasS proteins, respectively an ECF sigma factor and an anti-sigma factor. The signaling cascade is inducted by the binding of holo-hemophore (charged with heme) on the HasR receptor but neither by heme nor by apo-hemophore (not charged with heme) that also bind to the HasR receptor. The stimulus triggering the signaling cascade can be separated in two elements necessary for induction: the heme landing on the HasR receptor and the presence of the 50-55 region of the HasA hemophore located in one of the two regions of interaction between the hemophore and the receptor. Neither the heme transport nor the recycling of the hemophore discharged of its heme seem to be necessary to trigger the signaling cascade of the Has system. The regulation of the expression of the hasl and hasS genes was also studied and we bring to light a new mode of regulation for sigma and anti-sigma factors in which the sigma factor Hasl regulates positively the expression of its anti-sigma factor HasS
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Chakraborty, Arka Pratim. "Studies on bacillus megaterium and serratia marcescens as plantgrowth promoter and biocontrol agents." Thesis, University of North Bengal, 2013. http://hdl.handle.net/123456789/962.
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Rossi, Maria-Silvia. "Etude des mécanismes d'acquisition du fer dépendant de la protéine extracellulaire HasA chez les bactéries à gram négatif Serratia marcescens et Yersinia pestis." Paris 7, 2004. http://www.theses.fr/2004PA077224.
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Parente, Ticiana Mon’tAlverne Lopes. "Perfil de resistência a antibióticos e a terapia fotodinâmica antimicrobiana exibida por isolados ambientais, orais e extra-orais de Serratia marcescens." reponame:Repositório Institucional da UFC, 2010. http://www.repositorio.ufc.br/handle/riufc/26268.
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PARENTE, T.M.L Perfil de resistência a antibióticos e a terapia fotodinâmica antimicrobiana exibida por isolados ambientais, orais e extra-orais de Serratia marcescens. 2010. 90 f. Dissertação (MESTRADO EM BIOTECNOLOGIA) - Campus de Sobral, Universidade Federal do Ceará, Sobral, 2010.Submitted by Djeanne Costa (djeannecosta@gmail.com) on 2017-09-04T10:52:07Z No. of bitstreams: 1 2010_dis_tmlparente.pdf: 2557651 bytes, checksum: 75c39a01d93208de5800a785cfa1c2ee (MD5)
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Made available in DSpace on 2017-10-03T14:53:42Z (GMT). No. of bitstreams: 1 2010_dis_tmlparente.pdf: 2557651 bytes, checksum: 75c39a01d93208de5800a785cfa1c2ee (MD5) Previous issue date: 2010
Serratia marcescens is widely distributed in nature, but has emerged in the last years as important nosocomial pathogen with resistance of many antimicrobial drugs. This study aimed to verify the susceptibility of Serratia marcescens isolates from environment, from oral infections and from extra-oral infections to different antibiotics and evaluate the antimicrobial effect of photodynamic antimicrobial therapy as biotechnology tools reducing bacterial growth in planktonic cells and biofilm. E-test® were performed for fifty-five strains and the PACT for the thirty strains more resistant to antimicrobials tested. The antimicrobial effect of toluidine blue O, associated with 4,72 J cm-2 of a light-emitting diode , was evaluated. Before and after the treatments, bacterial inocula were analysed with regard to the number of colony- forming units. For antimicrobials, we observed that the 55 strains analyzed, 13 (23.63%) were resistant to doxycycline, but only one (1.81%) isolate showed resistance to ciprofloxacin, another to tobramycin and another to cefotaxime, 24 ( 43.63%) strains had intermediate sensitivity to doxycycline, all were sensitive to imipenem and most were sensitive to ciprofloxacin, tobramycin and cefotaxime Statistical analysis showed no significant differences in resistance of samples of different origins for drugs DX, CT, and IP. Considering the resistance to CI, the environmental samples were significantly more resistant than samples oral and extra-oral. For the drug TM, the oral samples were significantly more sensitive than the other samples. The irradiation of planktonic and biofilm cultures in the absence of TBO (L+S-), incubation with TBO alone (L-S+) and untreated control group (L-S-) had no significant effect on the viability of strains of S. marcescens studied (p <0.05). Significant decreases in bacterial viability was observed only when planktonic and biofilm culture of environmental strains, oral and extra-oral S. marcescens were exposed to toluidine blue O and LED light at the same time (L+S+). Significant reductions in bacterial counts were observed by antimicrobial photodynamic therapy ranging from 10-11 to 10-7.The association of TBO and light, with energy density 4,72 J cm-2, was effective in reducing the viability of bacterial strains in environmental, oral and extra-oral S. marcescens and can be a useful biotechnological tool in the control of bacterial resistance.
Serratia marcescens se encontra largamente distribuída na natureza, mas tem emergido nos últimos anos como um importante patógeno nosocomial resistente a diversos antimicrobianos. Este estudo teve como objetivo verificar a susceptibilidade de isolados ambientais, orais e extra-orais de Serratia marcescens a diferentes antibióticos e avaliar a terapia fotodinâmica antimicrobiana na redução do crescimento bacteriano em culturas de células planctônicas e biofilme. O teste de susceptibilidade antimicrobiano E-test® foi realizado para as 55 cepas e o TFA para as 30 cepas mais resistentes aos antimicrobianos testados. O efeito antimicrobiano do azul de o-toluidina associado com 4,72 J cm-2 de luz emitida por um diodo (LED) foi avaliado. Antes e após os tratamentos, os inóculos bacterianos foram analisados com consideração do número de unidades formadoras de colônias. Considerando o perfil antimicrobiano observamos que das 55 cepas analisadas, 13 (23,63%) apresentaram resistência à doxiciclina, mas apenas um (1,81%) isolado apresentou resistência ao ciprofloxacino, outro à tobramicina e outro à cefotaxima; 24 (43,63%) cepas apresentaram sensibilidade intermediária à doxiciclina, todas foram sensíveis ao imipenem e a maioria foi sensível ao ciprofloxacino, à tobramicina e à cefotaxima. A análise estatística demonstrou não haver diferenças significativas no perfil de resistência das amostras de diferentes origens em relação as drogas DX, CT e IP. Considerando a resistência a CI, as amostras ambientais foram significativamente mais resistentes do que as amostras orais e extra-orais. Para a droga TM, as amostras orais foram significantemente mais sensíveis do que as demais amostras. A irradiação das culturas planctônicas e biofilmes na ausência de TBO (L+C-), a incubação com TBO sozinho (L-C+) e o grupo controle não tratado (L-C-) não apresentou efeitos significativos na viabilidade das cepas de S. marcescens estudadas (p < 0,05). Decréscimos significativos na viabilidade bacteriana foram observados somente quando cultura planctônica e biofilme de cepas ambientais, orais e extra-orais de S. marcescens foram expostas ao azul de orto toluidina e luz LED ao mesmo tempo (L+C+). Reduções significativas nas contagens bacterianas foram observadas pela Terapia Fotodinâmica Antimicrobiana com variação de 10-11 a 10-7. A associação de TBO e LED, com densidade de energia de 4,72 J cm-2 , foi efetivo na redução da viabilidade bacteriana em cepas ambientais, orais e extra-orais de S. marcescens podendo ser uma ferramenta biotecnológica útil no controle da resistência bacteriana.
30
Becker, Stefanie [Verfasser]. "Crystallographic studies on the outer membrane heme receptor HasR from Serratia marcescens / Stefanie Becker." Konstanz : Bibliothek der Universität Konstanz, 2012. http://d-nb.info/1027669891/34.
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Nehme, Nadine. "Study of host-pathogen relationships between Drosophila melanogaster and an entomopathogenic bacterium Serratia marcescens." Université Louis Pasteur (Strasbourg) (1971-2008), 2007. http://www.theses.fr/2007STR13095.
Full textAbstract:
J’ai établi un système d’infection par voie orale. L’étude de ce système d'infection intestinale de la drosophile m’a permis de démontrer l’importance de deux mécanismes complémentaires et indépendants de la défense de l’hôte : la réponse locale imd-dépendante au niveau de l’épithélium intestinal et la phagocytose par les plasmatocytes. J’ai participé à la caractérisation d’un nouveau récepteur de phagocytose, Eater. Les mouches dépourvues de ce récepteur sont plus sensibles à l’infection par S. Marcescens. Nous avons décidé d’utiliser cette propriété pour réaliser un crible au niveau du génome entier afin d’identifier tous les gènes impliqués dans la défense contre les infections intestinales. Nous avons criblé de manière exhaustive, par interférence à l’ARN double brin, une banque de 13760 lignées transgéniques1 permettant de cibler presque tous les gènes prédits du génome de la drosophileSerratia marcescens is an entomopathogenic bacterium that opportunistically infects a wide range of hosts, including humans. In the fly, S. Marcescens escapes from the gut and reaches the body cavity. We have demonstrated that two mechanisms act together against such food-borne infection : an immune-deficiency pathway-dependent antimicrobial response in the intestine and phagocytosis by blood cells in the hemolymph. In addition, a strong oxidative burst takes place in the gut lumen in response to the presence of microorganisms. The molecular dissection of the interaction between S. Marcescens and Drosophila, thanks to the genetic tools available in both host and pathogen, will provide a useful paradigm to decipher intestinal pathogenesis. The insights gained from this approach may also help us better understand intestinal innate immunity in vertebrates. We are using a third generation mutagenesis screen to identify all the genes involved in the host defense against S. Marcescens intestinal infections, using the Vienna transgenic RNAi library
32
Sina, Rahme Bechara. "Contributions to the study of host-pathogen interactions between Drosophila melanogaster and Seatia marcescens." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ093.
Full textAbstract:
L’étude des interactions hôte-pathogène permettra de mieux comprendre les bases des maladies infectieuses. Durant ma thèse, j’ai étudié les interactions entre l’organisme modèle Drosophila melanogaster et la bactérie pathogène à Gram négatif Serratia marcescens (S.m). Cette bactérie est capable de tuer les mouches en moins de 24 heures une fois introduite directement dans l’hémolymph. Au contraire, les mouches peuvent survivre plusieurs jours après avoir ingéré du Serratia malgré les dommages à l’épithélium intestinal qui en résulte. Le travail de ma thèse a mené à comprendre la virulence des vésicules de la membrane externe purifiés de S.m et injectés dans la mouche. En plus, nous avons mis en évidence deux gènes qui jouent un rôle dans la virulence de la bactérie en infection intestinale, notamment dans la capacité de S.m à endommager les cellules intestinales. Enfin, nous avons identifié plusieurs gènes impliqués dans un mécanisme de résilience de la drosophile aux infections intestinales par S.mThe study of host-pathogen interactions will provide a better understanding of the basics of infectious diseases. During my thesis, I studied the interactions between the model organism Drosophila melanogaster and the Gram-negative pathogen Serratia marcescens (S.m). This bacterium is capable of killing flies in less than 24 hours once introduced directly into the hemolymph. On the contrary, flies can survive several days after ingesting Serratia despite he resulting damages to the intestinal epithelium. The work of my thesis led to an understanding of the virulence of the outer membrane vesicles purified from S.m and injected into the fly. In addition, we have identified two genes that play a role in the virulence of the bacterium in the intestinal infection model, particularly in the ability of S.m to damage the intestinal cells. Finally, we have identified several Drosophila genes involved in a resilience mechanism to intestinal infections by S.m
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Llanes, Catherine. "Plasmides de resistance de serratia marcescens : typage de replicons, clonage et sequencage du replicon repa/c." Besançon, 1993. http://www.theses.fr/1993BESA3709.
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Rigotti, Marcelo Alessandro. "Segurança microbiológica na abertura de ampolas com ênfase no procedimento de desinfecção." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/22/22132/tde-05112012-201527/.
Full textAbstract:
O cuidado a saúde incorpora continuamente, novas tecnologias relacionadas a produtos e processos que podem trazer riscos, especialmente, quando não possuem embasamento técnico-científico. Ampolas de plástico são amplamente utilizadas no preparo de injetáveis, no entanto, a contaminação biológica das soluções na sua abertura é ainda questionável. Sabe-se que o risco de infecção tem etiologia multifacetada envolvendo aspectos complexos da microbiota endógena e das condições ambientais. O objetivo do estudo é contribuir para com a segurança microbiológica da abertura de ampolas com base no procedimento de desinfecção e, assim, minimizar os riscos de contaminação biológica no preparo de injetáveis. Trata-se de um experimento de laboratório que permitiu avaliar a esterilidade do conteúdo das ampolas e, consequentemente produziu evidencias acerca da segurança microbiológica no preparo de injetáveis. Para determinação se a abertura de ampolas possibilita veiculação bacteriana para as soluções utilizaram-se dois métodos de desinfecção do gargalo um com suabe e outro com algodão ambos umedecidos em álcool a 70%. Das 120 ampolas de plástico com água esterilizada 60 tiveram seus gargalos contaminados intencionalmente com Serratia marcescens (ATTCC 14756) e outra metade com Staphylococcus aureus resistente à meticilina (MRSA) (ATTCC 43300) na ordem de 106 UFC/mL. Na abertura das respectivas ampolas utilizaram-se os princípios e o rigor de assepsia em termos de higiene das mãos e uso de luvas esterilizadas. Na avaliação da positividade das culturas uma alíquota da solução de cada ampola foi pipetada em caldo nutriente e incubada a 35ºC por 14 dias. A fricção dos gargalos das ampolas com suabe ou bolas de algodão embebidas em 3 ml de álcool a 70% não foi eficaz na redução da contaminação do conteúdo destas ampolas. Evidencia-se que houve maior contaminação nas ampolas, intencionalmente contamindas com Serratia marcescens, que receberam desinfecção com suabe 19 (63,3%) comparado as ampolas 15 (50%) que foram desinfetadas com bolas de algodão embebidas em álcool. As ampolas contaminadas com Staphylococcus aureus resistente à meticilina independentemente de utilizar suabe ou bolas de algodão embebidas em álcool, a contaminação do conteúdo das ampolas foi alta 24 (80%) e 18 (60%), respectivamente. Das 60 (100%) ampolas contaminadas com Serratia marcescens 34 (56,7%) apresentaram contaminação da água destilada e, das 60 (100%) ampolas contaminadas com Staphylococcus aureus resistente à meticilina, 42 (70%) apresentaram contaminação. A elucidação do processo de contaminação do conteúdo de ampolas de plástico durante sua abertura é urgente, especialmente considerando a possibilidade do contato da solução com o meio externo e vice- versa. Consta-se que a temática carece de mais investimentos de pesquisa dado a relevância do procedimento de desinfecção na redução da carga microbiana.The health care incorporates continuously new technologies related to products and administration processes that may pose risks, especially when there is no technical- scientific basis. Plastic ampoules are widely used in the preparation of injectables, however, biological contamination in solutions at its opening is still questionable. It is known that the risk of infection presents a multifaceted etiology involving complex aspects of endogenous microbiota and environmental conditions. The present investigation was carried out in order to contribute to the microbiological safety of opening ampoules based on disinfection procedure and thereby minimize the risk of biological contamination in the preparation of injectables. This is a laboratory experiment that allowed to evaluate the sterility of ampoules´ contents and consequently produced evidences regarding the microbiological safety in the preparation of injectables. To determine whether the opening of ampoules allows the carrying of bacteria into the solutions it was used two methods of ampoule neck disinfection, one with cotton balls and another with cotton swab both soaked with 70% alcohol. Of the 120 plastic ampoules containing sterile water, 60 had the ampoules necks intentionally contaminated with Serratia marcescens (ATTCC 14756) and the other half with methicillin-resistant Staphylococcus aureus (MRSA) (ATTCC 43300) of the order of 106 CFU/mL. At the opening of respective ampoules it was used the principles of strict asepsis and rigor in terms of hand hygiene and use of sterile gloves. In the evaluation of positive cultures an aliquot of solution from each ampoule was pipetted in nutrient broth and incubated at 35 °C for 14 days. Rub the ampoules necks with swab or cotton balls soaked with 70% alcohol in 3 ml was not effective in decreasing contamination of contents of those ampoules. It is evident that there were more contamination in ampoules intentionally contaminated with Serratia marcescens which received disinfection with swabs 19 (63.3%) if compared ampoules disinfected with cotton balls soaked in alcohol 15 (50%). Ampoules contaminated with methicillin-resistant Staphylococcus aureus neither swab nor cotton balls soaked in alcohol was effective, contamination of the contents of the ampoules 24 was high (80%) and 18 (60%), respectively. Of the 60 (100%) ampoules contaminated with Serratia marcescens 34 (56.7%) had distilled water contaminated, and from 60 (100%) ampoules contaminated with methicillin-resistant Staphylococcus aureus, 42 (70%) were contaminated. The elucidation of contamination process of contents of plastic ampoules during its opening is an urgent need, especially considering the possibility of contact of the solution with the external environment and vice versa. The evidence suggests that the issue needs more research investments given the relevance of the disinfection procedure in decreasing microbial load.
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Schmoranz, Michal. "Diferenciace bakteriálních kolonií Serratia marcescens." Master's thesis, 2008. http://www.nusl.cz/ntk/nusl-290855.
Full textAbstract:
We explain the typical shape and appearance of bacterial monocolonies grown on rich medias as an active effort of cooperating individuals. This puts each colony into the light of biological aesthetics and shows it as a unique piece of art. We understand the appearance of colonies as a manifestation of the most general dimension of Life, enabled by domestification and relaxing of the stress of natural selection. That is, what allows the colonies to experiment in their morfogeny and to resign on the functional morfogenesis. When kept in convenient conditions, aerobic bacteria tend to build complex colonies with strain specific patterns. The colonies are suprisingly well organised considering that they are built by more than 10 000 times smaller primitive unicellular organisms. In microbiology the colour and shape pattern of the colonies used to be called "the secondary metabolism". Nowadays we consider them to be an effect of the efficient microbial communication and we know, that bacteria have utilized for communication hundreds of different biochemical messages. However, we still do not understand the relevance or the aim of the formation of the colonies and their pattern. Moreover, we are also able to detect a complicated intercolonial behaviour including in some cases cooperation, agressiveness...
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(6650222), Danielle Susan Sopovski. "Antimicrobial Resistance in Serratia marcescens." Thesis, 2019.
Find full textAbstract:
With
the increase of antibiotic resistant bacteria strains, the need to determine
the mechanisms of antimicrobial resistance is similarly rising. Serratia marcescens, a ubiquitous,
Gram-negative opportunistic pathogen is known to have strong, natural
resistance to diverse antimicrobial agents including antibiotics and
antimicrobial peptides. Recently, we identified S. marcescens as one of the few bacteria resistant to antimicrobial
compounds produced by Stemphylium
vesicarium, an isolated fungal spinach endophyte. To identify the mechanism
of antimicrobial resistance to the unknown Stemphylium
antimicrobial compounds, we designed a transposon mutant screen identifying
mutants sensitive to antimicrobial inhibition of bacterial growth. A transposon
mutant library was constructed using the Tn5 EZ-Transposome (Epicentre) system and
contains 1,824 individual mutants with 127 being identified as having a
decreased resistance to the Stemphylium
antimicrobial compounds. The transposon growth inhibition screen initially evaluates
the mutants for reduced growth in the presence of 25% fungal metabolite over 24
hours. The growth phenotype is then confirmed
in triplicate in a 12-hour time course growth experiment. Identification of the
genomic insertion site of the Tn5 transposon utilized a multi-step modified
nested-PCR protocol, termed TAIL-PCR. Following PCR purification, nanodrop
spectroscopy and gel electrophoresis were performed to ensure the amplification
purity of the extracted DNA and was subsequently sequenced via WideSeq analysis.
BLAST identified insertions in genes necessary for membrane biogenesis, drug
transport, pili formation, and iron metabolism. Future work is aimed at
confirming these results and understanding the role of iron sequestration. Not
only will this research contribute to our understanding of S. marcescens antimicrobial resistance mechanisms, but it aids in
our understanding of the mechanisms of antimicrobial resistance development in
other human pathogens.
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Lin, Yu Cing, and 林育青. "The RssB regulon of Serratia marcescens." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/27744368538592844659.
Full textAbstract:
碩士長庚大學
醫學生物技術研究所
97
Bacterial swarming is a primitive cell differentiation and multicellular behaviour. Using Serratia marcescens as a study model, previously we had identified a pair of two-component system RssA-RssB negatively regulating swarming initiation, especially at the swarming lag phase. However, the underlying mechanism remains unclear. Using pull-down assay, a total of about 50 gene promoters was previously identified to be bound by phosphorylated RssB (RssB~P). To further characterize the interaction between RssB~P and the promoters of these genes, electrophoretic mobility shift assay (EMSA) was performed. At least 15 promoters of genes involved in diverse functions were directly bound by RssB~P with different binding affinity. Reverse transcription and real-time quantitative PCR were used to evaluate effect of RssB~P on transcription level of these genes in bacterial cells grown in different phases. Among the genes whose promoters directly bound by RssB~P, 8 of them were differentially expressed between the parent S. marcescens CH-1 and rssBA deleted cells in late log phase, and 10 genes were differentially expressed before and after swarming initiation. The results of this study imply that RssA-RssB signalling may involve DNA synthesis, virulence, carbon metabolism and chromosome partition to regulate swarming initiation. Taken together, this study offers some clues to explain the role of RssA-RssB signaling during early swarming development.
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Rieger, Tomáš. "Morfogeneze mnohobuněčných těl u bakterie Serratia marcescens." Master's thesis, 2007. http://www.nusl.cz/ntk/nusl-374287.
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Wu, Yue-Jin, and 吳岳進. "Characterization of Mutated Chitinase from Serratia Marcescens." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/09715014964651952714.
Full textAbstract:
碩士國立交通大學
應用化學系
91
A chitinase gene of Serratia marcescens (ChiA) was PCR cloned. The ChiA was further constructed into pRSETA vector and transformed into Escherichia coli JM109 cells for protein expression. DNA sequence analysis and comparison revealed that the region requires for protein expression involving an open reading frame of 1689 base pairs, correspondent to 563 amino acids with a N-terminal signal peptide of 23 residues. An intracellular chitinase was further purified to＞90% homogeneity by the hydrophobic interaction chromatography following by ion-exchange separation. Chitobiose is the predominant product through out the enzymatic hydrolysis of the colloidal chitin, indicating that the purified chitinase is an exo-chitinase. In addition, the gene was mutagenized to insert an extra disulfide bond between residues 441 and 521, 521 and 551. The activities and the end product (chitobiose) of these doubly mutated enzymes did not perturbed. With the application of the wild-type chitinase, a 10-gramed scale reaction was performed for chitobiose preparation.
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Koh, Kai-Shyang Biotechnology & Biomolecular Sciences Faculty of Science UNSW. "Evolution and phenotypic diversification in serratia marcescens biofilms." 2007. http://handle.unsw.edu.au/1959.4/40588.
Full textAbstract:
The release of cells from a biofilm to the surrounding environment is poorly understood and the importance of this stage of biofilm development has only recently been realized. A key part of this process is the generation of phenotypic variants in the biofilm dispersal population. This thesis reports on the characterization of biofilm development of Serratia marcescens MG1, the analysis of the biofilm dispersal population, and the identification of the conditions that trigger phenotypic diversification. Furthermore, it provides an insight into the molecular understanding of how phenotypic variation is being generated, and demonstrates the clinical and environmental implications of phenotypic diversification during bacterial pathogenesis and bacterial persistence. Characterization of the microcolony biofilm development of S. marcescens revealed that the S. marcescens biofilm develops through a process involving microcolony formation, hollowing of mature microcolonies, and a sudden biofilm expansion within a very short period (< 24h) resulting in an increase in biofilm biomass with a radiation of biofilm structures at days 3 to 4. The biofilm expansion phase consistently correlated to an increase in the number of dispersal variant morphotypes. Studies of variant induction in planktonic cultures and biofilm flow cells demonstrated that phenotypic diversification in S. marcescens is not only a biofilm-specific phenomenon, but also involves biofilm-specific morphotypes. These morphological variants can only be isolated from the microcolony biofilm morphotype and not from the filamentous biofilms, leading to the hypothesis that there is a strong diversifying selection that is specific to the microcolony biofilms. To further explore how these variants were generated, molecular analyses revealed that exopolysaccharides and lipopolysaccharides are important moieties that are involved in phenotypic variation in S. marcescens biofilms. The etk gene, encoding a tyrosine protein kinase within the exopolysaccharide biosynthesis operon, was found to contain single nucleotide polymorphisms (SNPs) that were present in the 'sticky' variants but not in the 'non-sticky' wild-type or the 'non sticky' small colony variants. Furthermore, infrequent-restriction-site PCR (IRS-PCR), BIOLOG metabolic profiling, and gene sequence analyses, suggest that phenotypic diversification in S. marcescens is likely to involve mutational hotspots in specific genes. The biofilm-derived morphotypic variants differed extensively in cell ultrastructure properties, and exhibited specialized colonization and virulence traits, such as attachment, biofilm formation, swimming and swarming motilities, protease production, and hemolysin production. It was also demonstrated that phenotypic diversification contributed to a varying degree of resistance to protozoan predation, and bacterial pathogenecity in Caenorhabditis elegans, highlighting the complexity of the dispersal populations from S. marcescens biofilms. Furthermore, mixed-culture experiments involving multiple variant isolates (with or without the parental wild-type) showed that the persistence and virulence potential of S. marcescens can be synergistically enhanced in the Acanthamoeba castellanii grazing model and in the C. elegans infection model, respectively. This indicates that the different bacterial morphotypes work in concert to provide S. marcescens with enhanced protection against environmental perturbations and a competitive edge during the infection process. It was proposed that phenotypic diversification is not only an integral part of S. marcescens biofilm life-cycle, but also represents an important strategy for bacteria to greatly enhance its survival and persistence in different environments, ranging from aquatic and soil ecosystems, to those of the infected hosts.
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Kumar, Ayush. "Characterization of RND efflux pumps of Serratia marcescens." 2005. http://hdl.handle.net/1993/20140.
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蔣捷名. "Protein Engineering of the Chitinases from Serratia marcescens." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/33245346416402343201.
Full textAbstract:
碩士國立海洋大學
水產生物技術研究所
90
The gene encoding the chitinases (chi22) from Serratia marcescens was amplified from its chromosomal DNA by PCR techniques. The full-length chitinase (chi22) gene of S. marcescens is consisted of 675 base pairs and encode 225 amino acid residues. The recombinant chitinase was expressed in E. coli BL21(DE3)pLysS as insoluble inclusion bodies and were difficult to be renatured. A site-directed mutagenesis of S. marcescens chitinase gene was performed by PCR based on the amino acid sequence homology comparision of the chitinases among S. marcescens Chi(L38484) and S. marcescens Chi(AB015998). The mutant gene SMchi22mut was cloned and expressed as a soluble protein from the bacterial expression host E. coli BL21(DE3)pLysS. Unfortunately, it had no chitinase activity. DNA shuffling and Error prone PCR were both used to mutate SMchi22mut gene. Any mutant with significant chitinase activity were not found. The second site-directed mutation of SMchi22mut gene was performed by PCR based on the amino acid sequence homology comparision. Again, it failed to have any clones with chitinase activity.
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Lin, Chuan-Sheng, and 林詮盛. "RssAB Controls Virulence and Pathogenesis in Serratia marcescens." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/06362946146891392799.
Full textAbstract:
碩士國立臺灣大學
醫學檢驗暨生物技術學研究所
96
Serratia marcescens, as an important opportunistic pathogen, presents different multicellular behaviors like swarming and biofilm and possesses many virulence factors to adapt to diverse environments. However, the underlying mechanism of coordinating multicellularity, virulence expression, and pathogenesis of S. marcescens is unclear. Here, we show that two component system RssAB acts as an antivurlence modulator and inactivation of rssBA leads to hypervirulence phenotype of S. marcescens compared with wild type strain in acute pneumonia model of rat. Furthermore, RssAB inversely regulates swarming motility and early biofilm formation accompanied with contrary of expression of dominant virulence factor hemolysin ShlA. Associated with precocious swarming and defect in early biofilm formation, deletion of rssBA causes S. marcescens elevated hemolysin production concomitant with rising cytotoxicity and invasion against to human bronchial epithelial cell owing to derepression of flhDC in transcription level. Furthermore, in sublethal pneumonia model, we find that RssAB determine the capability of S. marcscens to cause systemic infection through modulating hemolysin. Without RssAB, this fine tuning in host-pathogen balance will lose and be toward to hypervirulent phenotypes during S. marcescens infection. We propose that S. marcescens utilizes RssAB to coordinate different multicellular behaviors and moderate virulence factor expression.
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ZHANG, ZHI-XUAN, and 張士軒. "Pigment production of serratia marcescens and its application." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/99030012731495366789.
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Lin, Chuan-Sheng. "RssAB Controls Virulence and Pathogenesis in Serratia marcescens." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-0407200815524800.
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Serepa, Mahloro Hope. "Is Serratia marcescens strain MCB an entomopathogenic bacterium?: a focus on genomics." Thesis, 2016. http://hdl.handle.net/10539/21071.
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In Fulfilment for the requirements for the degree of
Doctor of Philosophy
University of the Witwatersrand
Johannesburg, South Africa
Thesis Defended 23 September 2015The phylum nematoda has a variety of functional groups. The parasitic functional group comprise various nematodes some which are parasitic to insects and are known as entomopathogenic nematodes (EPNs). The two most studied genera of EPNs are Steinernema and Heterorhabditis. These EPNs are associated symbiotically with the two enterobacteria genera; Xenorhabdus and Photorhabdus, respectively. The explanation of EPNs has been recently expanded to include the genus Oscheius which have been found to be associated with Serratia species. The bacteria synthesize a range of insecticidal and antimicrobial metabolites which may be useful in various ways as agricultural pest control and medical disease control. An insight into the genome of the nematode-bacterium duo will provide us with information about the symbiosis between the two and parasitism against insect pests. Here in I discuss the isolation and identification of a South African EPN and its symbiotic bacterium. In addition I highlight the production of indole derivatives which are common metabolites produced by entomopathogenic bacteria. The thesis eventually describes and discusses the methods for whole genome sequencing of both the isolated nematode and its symbiotic bacterium, and the genomic content indicate similar genes with other known EPN genera and protein-coding genes involved in symbiosis and parasitism.
MT2016
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Hutsul, Jo-Anne Marie. "Characterization of the outer membrane porins of Serratia marcescens." 1996. http://hdl.handle.net/1993/19192.
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Ding, Ying-Xiu, and 丁映秀. "Optimal production of prodigiosin by Serratia marcescens YOR-1." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/22606318035622281281.
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碩士輔仁大學
生命科學系碩士班
101
Prodigiosin is one of secondary metabolites produced by Serratia marcescens, Vibrio psychroerythrus, Hahella chejuensis, Pseudomonas magnesiorubra. Prodigiosin has many bio-activities like anti-cancer ,anti-bacterial, anti-malarial, anti-algae activity and many more applications. Therefore, find the optimal condition to increase the production yield of prodigiosin is very important for industrial production. In this study, we used S. marcescens YOR-1 which could produce prodigiosin was isolated from environment. The first step, we modify the formula of the basic medium（nutrient broth）. Modified nutrient broth content the concentration of 0.4000% peptone and 0.2000% beef extract. Next, we compare the producing yield of prodigiosin in solid-state culture and liquid culture. We also compare the different in solid-state culture and liquid culture. The result indicate large culture volume in liquid culture will reduced prodigiosin production yield, but not affected in solid-state culture. Beside this, we also discovered the prodigiosin yield in solid-state culture is 1.83 times higher than the liquid culture. Therefore, in this study, we used solid-state culture methods to produce prodigiosin, and test different nitrogen source and different carbon source to used in the prodigiosin production by S.marcescens YOR-1.The highest prodigiosin production yield was observed in malt extract and fructose. The experimental design was used to optimize the medium constituents for maximal prodigiosin production yield by S. marcescens. Results showed that the optimal medium constituents were 0.0039% malt extract and 0.6086% fructose. Under this optimal composition, the prodigiosin production yield was 4.2881 g/L.
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Lin, Yuan-Ju, and 林芫如. "Study on Chitinolytic Enzymes from Serratia marcescens NTU-17." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/44846555575249611399.
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碩士國立臺灣大學
生物產業機電工程學研究所
96
Abstract N-acetylchitooligosaccharides (degree of polymerization 4-6) have specific biological activities such as antitumor activity and immuno-enhancing effects. In this study, we aimed to isolate environmental microorganisms which could produce enzymes to hydrolyze chitin into N-acetylchitooligosaccharides. At the initial stage, we hydrolyzed colloidal chitin with crude microbial enzymes and analyzed the products by HPLC. From this screening, we found that the crude enzyme from one bacterial isolate could hydrolyze chitin and produce N-acetylchitooligosaccharides. The bacterial strain was identified by 16S rRNA sequencing and phylogenetic analysis to belong Serratia marcescens and was named S. marcescens NTU-17. We used central composite design (CCD) of response surface methodology (RSM) to obtain the optimal culture condition for chitinase production: 0.4 g/l colloidal chitin, 1.6 g/l casein, 30。C and pH 7.5; the highest chitinase activity was produced at 18 hours after inoculation. The crude enzyme from culture broth of S. marcescens NTU-17 was subjected to successive steps of purification. After ammonium sulfate fractionation (35-70%), gel filtration-Sephacryl 200 chromatography, and DEAE-Sephacel column chromatography, two species of chitinase were purified and the molecular weights were determined by SDS-PAGE to be 53 kDa (chitinase 1) and 39 kDa (chitinase 2). The chitinase activity of chitinase 1 and 2 were also verified by an in-gel chitinase activity assay. After purification, the specific activity of chitinase was increased by 2.5 fold and the yield was 12%. Chitinase 1 exhibited the optimal activity at pH 3 and 50℃, and chitinase 2 showed the optimal activity at 30℃ and similar activities at pH 3-12.
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Lin, Chien, and 林芊. "Studies on the production of prodigiosin by Serratia marcescens." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/44331036610361516196.
Full textAbstract:
碩士國立臺灣大學
農業化學研究所
93
Prodigiosin is the red pigment produced by microorganisms such as Serratia marcescens, Pseudomonas spp., Streptomyces spp., etc. Recently, the immunosuppressive and apoptotic activities of prodigiosin have been described. Therefore, prodigiosin seems to be a promising compound for the usages in the functional food, new immunosuppressants and anti-cancer drugs. In this study, the yield of the prodigiosin produced by S. marcescens BCRC 11576 reached 48 mg/100mL broth after incubation in 1.4% soybean flour broth at 27℃ with vigorous shaking for 48 hours. This yield was the highest of all previously reported. Besides, it was found that the prodigiosin production of this strain was affected greatly depending on the composition of medium. When this strain was incubated in the presence of glucose with the glucose-to-nitrogen source ratio reached to a certain value, no prodigiosin was produced and the pH of the broth dropped quickly to a value below 3. Buffering the broth between pH 7 and pH 9 during incubation released the inhibition resulted from addition of glucose to the broth. Consequently, the inhibitory effect of glucose on prodigiosin production may be due to a lowering of the pH of the medium. S. marcescens BCRC 11576 was incubated in 1.4% soybean flour broth for 48 hours (the yield of the prodigiosin was 0.46 g/L). After 1 L broth was centrifuged, the cell pellets extracted with methanol and obtained 1.9 g of the crude extract pigment. The crude extract was purified by silica gel chromatography and the prodigiosin was eluted with ethyl acetate. The amount and the purity are 0.18 g and 94%, respectively. The purified prodigiosin showed no significant mutagenesis analyzed by the mouse lymphoma tk assay with the prodigiosin concentration between 0.8 and 8 mM. This result increased the safety for the use of prodigiosin.