Tesis sobre el tema "Pyocyanin"
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Price-Whelan, Alexa Mari Leadbetter Jared R. Newman Dianne K. "Physiology and mechanisms of pyocyanin reduction in pseudomonas aeruginosa /". Diss., Pasadena, Calif. : Caltech, 2009. http://resolver.caltech.edu/CaltechETD:etd-02182009-100346.
Texto completoLarian, Nika. "PYOCYANIN, A VIRULENCE FACTOR PRODUCED BY SEPSIS-CAUSING PSEUDOMONAS AERUGINOSA, PROMOTES ADIPOSE WASTING AND CACHEXIA". UKnowledge, 2019. https://uknowledge.uky.edu/pharmacol_etds/31.
Texto completoPan, Ninyuan y 潘寧遠. "The effects of pseudomonas aeruginosa pyocyanin on interleukin-8 expression in bronchial epithelium and therapeutic implications inbronchiectasis". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B45012866.
Texto completoWally, Hassan. "Identification and Characterization of MvaT and MvaU Global Regulators in Arginine Catabolism and Quorum Sensing of Pseudomonas aeruginosa". Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/biology_diss/16.
Texto completoPan, Ninyuan. "The effects of pseudomonas aeruginosa pyocyanin on interleukin-8 expression in bronchial epithelium and therapeutic implications in bronchiectasis /". View the Table of Contents & Abstract, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36432660.
Texto completoSILVA, Tacilene Luzia da. "Atividade sinérgica do timol e agentes antimicrobianos frente à Pseudomonas aeruginosa multirresistente e seus efeitos sobre a biossíntese de biofilme e piocianina". Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/16574.
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CNPq
Pseudomonas aeruginosa é uma bactéria Gram negativa, oportunista e ubíqua, frequentemente associada a infecções graves em pacientes imunocomprometidos. Em razão do aumento de resistência dessa bactéria aos múltiplos antimicrobianos, surgem à preocupação e a procura por novas alternativas terapêuticas, com as substâncias bioativas de origem natural representando uma importante fonte para obtenção desses medicamentos. O objetivo do presente estudo foi determinar a atividade sinérgica do timol e agentes antimicrobianos frente a cepas de Pseudomonas aeruginosa multirresistentes e avaliar os efeitos dessa interação sobre a biossíntese de biofilme e de piocianina. Para isso, numa primeira etapa foi determinada a concentração inibitória e bactericida mínima do timol e de antimicrobianos (Polimixina B, ceftazidima, piperacilina/tazobactam, cefepima, ciprofloxacino e meropenem) frente a dez cepas de Pseudomonas aeruginosa. O estudo da interação entre o timol e os agentes antimicrobianos foi realizado pelo método do tabuleiro de xadrez. Os critérios utilizados para avaliar a atividade sinérgica foram definidos pelo Índice da Concentração Inibitória Fracionada (FIC índex). A partir dos melhores valores do FIC índex das associações timol/antimicrobiano foram avaliadas a atividade sobre a produção de biofilme e piocianina. Três cepas (LFBM 01, LFBM 02, LFBM 16) apresentaram um perfil de resistência ao meropenem e cefepima e um efeito sinérgico foi observado entre o timol e meropenem ou cefepima sobre essas cepas. A associação timol/cefepima inibiu a biossíntese do biofilme em até 99,76%, e a associação timol/meropenem mostrou ser mais eficaz na inibição da piocianina cujos valores foram de até 84,33%. O timol associado ao meropenem ou cefepima, age sinergicamente, inibindo cepas de Pseudomonas aeruginosa multirresistentes e interferindo na biossíntese de biofilme e piocianina.
Pseudomonas aeruginosa is a Gram negative bacteria, opportunistic and ubiquitous, often associated with severe infections in immunocompromised patients. Due to the increased resistance of the bacteria to multiple antibiotics, there are the concerns and the search for new therapeutic alternatives, with the bioactive substances of natural origin represents an important source for obtaining these drugs. The aim of this study was to determine the synergistic activity of thymol and antimicrobials agents multiresistant Pseudomonas aeruginosa strains and evaluate the effects of this interaction on the biofilm biosynthesis and pyocyanin. For this, a first step was determined and the minimum inhibitory concentration of thymol and bactericidal antibiotics (polymyxin B, ceftazidime, piperacillin / tazobactam, cefepime, ciprofloxacin and meropenem) compared to ten strains of Pseudomonas aeruginosa. The study of the interaction between the thymol and antimicrobial agents was carried out by the checkerboard method. The criteria used to evaluate the synergistic activity were defined by the Index of Fractional Inhibitory Concentration (FIC index). From the best FIC index values of associations thymol / antimicrobial activity were evaluated on the production of biofilm and pyocyanin. Three strains (LFBM 01, LFBM 02, LFBM 16) showed an meropenem resistance profile and cefepime and a synergistic effect was observed between the thymol and meropenem or cefepime on these strains. The thymol / cefepime combination inhibited biofilm biosynthesis up to 99.76%, and thymol association / meropenem was more effective in inhibiting pyocyanin with values of up to 84.33%. The thymol associated with meropenem or cefepime, acts synergistically by inhibiting multidrug-resistant Pseudomonas aeruginosa strains and interfering in the biosynthesis of biofilm and pyocyanin.
Barakat, Rana. "Etude des propriétés biologiques et antimicrobiennes de la pyocyanine, pigment redox-actif produit par Pseudomonas aeruginosa". Phd thesis, Université de La Rochelle, 2012. http://tel.archives-ouvertes.fr/tel-00825873.
Texto completoCheluvappa, Rajkumar. "Pathophysiology of Liver Sinusoidal Endothelial Cells". Thesis, The University of Sydney, 2008. http://hdl.handle.net/2123/2802.
Texto completoCheluvappa, Rajkumar. "Pathophysiology of Liver Sinusoidal Endothelial Cells". University of Sydney, 2008. http://hdl.handle.net/2123/2802.
Texto completoOwing to its strategic position in the liver sinusoid, pathologic and morphologic alterations of the Liver Sinusoidal Endothelial Cell (LSEC) have far-reaching repercussions for the whole liver and systemic metabolism. LSECs are perforated with fenestrations, which are pores that facilitate the transfer of lipoproteins and macromolecules between blood and hepatocytes. Loss of LSEC porosity is termed defenestration, which can result from loss of fenestrations and/ or decreases in fenestration diameter. Gram negative bacterial endotoxin (Lipopolysaccharide, LPS) has marked effects on LSEC morphology, including induction LSEC defenestration. Sepsis is associated with hyperlipidemia, and proposed mechanisms include inhibition of tissue lipoprotein lipase and increased triglyceride production by the liver. The LSEC has an increasingly recognized role in hyperlipidemia. Conditions associated with reduced numbers of fenestrations such as ageing and bacterial infections are associated with impaired lipoprotein and chylomicron remnant uptake by the liver and consequent hyperlipidemia. Given the role of the LSEC in liver allograft rejection and hyperlipidemia, changes in the LSEC induced by LPS may have significant clinical implications. In this thesis, the following major hypotheses are explored: 1. The Pseudomonas aeruginosa toxin pyocyanin induces defenestration of the LSEC both in vitro and in vivo 2. The effects of pyocyanin on the LSEC are mediated by oxidative stress 3. Defenestration induced by old age and poloxamer 407 causes intrahepatocytic hypoxia and upregulation of hypoxia-related responses 4. Defenestration of the LSEC seen in old age can be exacerbated by diabetes mellitus and prevented or ameliorated by caloric restriction commencing early in life
McPhillips, Kathleen Ann. "The role of oxidants in the clearance of apoptotic cells /". Connect to full text via ProQuest. IP filtered, 2006.
Buscar texto completoTypescript. Includes bibliographical references (leaves 112-124). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;
Nascimento, Ana Paula Barbosa do. "Um novo gene de Pseudomonas aeruginosa envolvido em percepção de quórum". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/46/46131/tde-30092014-143752/.
Texto completoPseudomonas aeruginosa is a gammaproteobacterium that colonizes several environments and infects phylogenetically distinct hosts. It behaves as an opportunistic pathogen in humans, often related to infection in immunocompromised individuals and cystic fibrosis patients. An important mechanism for P. aeruginosa versatility is the quorum sensing (QS) network, that allows bacteria to link gene expression to population density and environmental traits. Several additional regulators are interconnected with QS, as the regulatory mRNA binding protein RsmA and the non-coding small RNAs RsmZ and RsmY. Futhermore, key factors for pathogenicity are QS-regulated. In P. aeruginosa PA14, an important pathogenicity-related factor is the KerV protein, described for the first time here as involved in QS. D12 strain, that harbor a deletion in the kerV gene, shows alterations in QS-regulated phenotypes, such as high production of pyocyanin, a compound that contributes to virulence and persistence of P. aeruginosa infections. As the production of pyocyanin is easily detected and all mechanisms involved in its synthesis regulation are not fully described, the expression of genes responsible for production of this pigment is a good reporter to investigate KerV involvement in the QS network. Additionally, D12 also shows lower levels of rhamnolipids, another QS-regulated trait. Taken together, these phenotypes resemble the effects of a rsmA mutation, suggesting KerV involvement with QS and Gac-Rsm systems. In this work, we propose that KerV exerts a negative effect in the regulation of phz1 and phz2 operons, responsible for pyocyanin synthesis, by alterating the expression of these genes. KerV also has a positive effect on rsmA expression, responsible for the repression of several genes by blocking the ribosome binding site preventing the translation. Gel shift assays showed that RsmA binds directly in the leader sequence of phzA1 and phzA2, elucidating the manner in which KerV is involved in the regulation of phz operons expression in P. aeruginosa PA14. We also demonstrate that phz2 is actively expressed and contributes to pyocyanin production in PA14, since in the phz1 mutant the levels of pyocyanin are even higher than in the wild type strain. This suggests a phz2 higher expression and a differential regulation of phz operons according to environmental changes as a mechanism to maintain the levels of pyocyanin synthesis. An evidence for this regulation is the synthesis of pyocyanin by the lasR mutant, which does not make pyocyanin at early growth stages. However, at late stationary phase, pyocyanin production is even higher than in the wild-type strain, reflecting the LasR-independent regulation of phz1 expression, while phz2 operon remains silent.
Price-Whelan, Alexa Mari. "Physiology and Mechanisms of Pyocyanin Reduction in Pseudomonas aeruginosa". Thesis, 2009. https://thesis.library.caltech.edu/674/1/pricewhelan_21809.pdf.
Texto completoThe opportunistic pathogen Pseudomonas aeruginosa excretes redox-active small molecules called phenazines. This thesis addresses the possibility that the phenazine pyocyanin acts as an electron acceptor for energy metabolism and exerts beneficial effects on P. aeruginosa physiology. The effects of phenazine production and exposure on P. aeruginosa strain PA14 were examined by comparing the physiological status of the wild type to a mutant defective in phenazine production. Quantification of intracellular NADH and NAD+ pools revealed a more reduced intracellular redox state in the phenazine-null mutant compared to the wild type, consistent with the capacity of P. aeruginosa to reduce pyocyanin. High-performance liquid chromatography of culture metabolites showed that the wild type excreted pyruvate in late stationary phase, indicating that pyocyanin alters flux through central metabolic pathways.
We set out to identify mechanisms allowing P. aeruginosa to catalyze pyocyanin redox cycling. Through a genetic screen, we found two loci required for full pyocyanin-dependent ferric citrate reduction activity in P. aeruginosa PA14: (1) the gene gpsA, encoding the soluble glycerol-3-phosphate dehydrogenase (GpsA), and (2) the operon fbcFBC, encoding the respiratory cytochrome bc1 complex. Mutants lacking functional GpsA had oxidized cytoplasms and may be defective in pyocyanin reduction due to a lack of sufficient NADH. In contrast, mutants lacking a functional cytochrome bc1 complex produced ample reducing power for pyocyanin reduction, raising the possibility that the cytochrome bc1 complex directly catalyzes pyocyanin reduction.
Pyocyanin has previously been shown to affect the development of P. aeruginosa colonies on agar surfaces: phenazine-null mutants form wrinkled (rugose) colonies, while the wild type forms smooth colonies. Using this colony biofilm assay, we showed that the ΔgpsA mutant forms rugose colonies, consistent with a role for pyocyanin reduction in stimulating smooth colony formation. Modulation of electron acceptor availability through nitrate addition to the medium promoted smooth colony formation in rugose mutants. These results imply that rugosity is an adaptation to electron acceptor limitation.
The work in this thesis has provided insight into the physiological relevance of pyocyanin reduction in P. aeruginosa, mechanisms controlling intracellular redox state in bacteria, and mechanisms that may contribute to P. aeruginosa virulence.
Liao, Yu-Hsuan y 廖祐瑄. "Regulation of pyocyanin biosynthesis by transcriptional regulator PsrA in Pseudomonas aeruginosa PAO1". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/dp4ww8.
Texto completoWang, Tzu-Hui y 王姿憓. "Studies on the Molecular Mechanisms for Seawater Affecting the Production of Pyocyanin in Pseudomonas aeruginosa". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/56063519964861686443.
Texto completo輔英科技大學
醫學檢驗生物技術系碩士班
100
Pseudomonas aeruginosa is an aerobic Gram-negative bacterial species and widely present in terrestrial, freshwater and marine environments that causes several opportunistic human infections. One important virulence factor, pyocyanin (PYO), is a blue-green pigment produced by Pseudomonas aeruginosa. Recent study demonstrated that production of pyocyanin by Pseudomonas aeruginosa was inhibited in saline stress condition but the mechanisms remain unknown. The major difference between freshwater and sea water is the constituents of salts. This study investigated the effects of salinity on bacterial growth, production of pyocyanin, mRNA expression of relevant genes, and protein-profile in Pseudomonas aeruginosa. The results indicated that Pseudomonas aeruginosa grew well in all conditions including media either with or without supplemented salts. However, the growth curves showed a log-phase-delay in media prepared with various concentrations of saline water. Furthermore, the pyocyanin was extracted and quantified. The results showed that the pyocyanin production of Pseudomonas aeruginosa cultured in medium with supplemented artificial sea water were 17% to 21% (24 h to 72 h) of those without supplemented salts. The decreases of pyocyanin were proportional to the concentrations of NaCl. Additionally, this study assessed the mRNA expression of phzM, phzS, and phz operon which are related to pyocyanin biosynthesis. The mRNA was measured using qRT-PCR. The results showed that decrease of pyocyanin was due to low mRNA expression of phzM, phzS, phzE, phzD, phzF, phzA1/ phzB1 and phzA2/phzB2 in artificial sea water. Finally, the effects of saline water on protein expression were analyzed by 2D gel electrophoresis and MALDI-TOF-TOF. The protein profiles for Pseudomonas aeruginosa cultured in media either with or without supplemented artificial sea water were compared. In conclusion, these results allow us to understand the molecular mechanisms for seawater affecting the production of pyocyanin in Pseudomonas aeruginosa.
Korgaonkar, Aishwarya Kiran 1983. "A mechanism for interspecies competition and virulence in Pseudomonas aeruginosa-containing polymicrobial infections". Thesis, 2012. http://hdl.handle.net/2152/ETD-UT-2012-08-6202.
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Montague, Gerard. "Impact of cell signals and pyocyanin on mixed-biofilms of Pseudomonas aeruginosa PaO1 and Escherichia coli K-12". Thesis, 2014. http://hdl.handle.net/1959.7/uws:36432.
Texto completoGohain, Neelakshi [Verfasser]. "Studies on the structure and function of phenazine modifying enzymes PhzM and PhzS involved in the biosynthesis of pyocyanin / eingereicht von Neelakshi Gohain". 2008. http://d-nb.info/997371889/34.
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