Academic literature on the topic 'Pyoverdine Pseudomonas fluorescen'
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Journal articles on the topic "Pyoverdine Pseudomonas fluorescen"
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Meyer, Jean-Marie, Valérie A. Geoffroy, Nader Baida, Louis Gardan, Daniel Izard, Philippe Lemanceau, Wafa Achouak, and Norberto J. Palleroni. "Siderophore Typing, a Powerful Tool for the Identification of Fluorescent and Nonfluorescent Pseudomonads." Applied and Environmental Microbiology 68, no. 6 (June 2002): 2745–53. http://dx.doi.org/10.1128/aem.68.6.2745-2753.2002.
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ABSTRACT A total of 301 strains of fluorescent pseudomonads previously characterized by conventional phenotypic and/or genomic taxonomic methods were analyzed through siderotyping, i.e., by the isoelectrophoretic characterization of their main siderophores and pyoverdines and determination of the pyoverdine-mediated iron uptake specificity of the strains. As a general rule, strains within a well-circumscribed taxonomic group, namely the species Pseudomonas brassicacearum, Pseudomonas fuscovaginae, Pseudomonas jessenii, Pseudomonas mandelii, Pseudomonas monteilii, “Pseudomonas mosselii,” “Pseudomonas palleronii,” Pseudomonas rhodesiae, “Pseudomonas salomonii,” Pseudomonas syringae, Pseudomonas thivervalensis, Pseudomonas tolaasii, and Pseudomonas veronii and the genomospecies FP1, FP2, and FP3 produced an identical pyoverdine which, in addition, was characteristic of the group, since it was structurally different from the pyoverdines produced by the other groups. In contrast, 28 strains belonging to the notoriously heterogeneous Pseudomonas fluorescens species were characterized by great heterogeneity at the pyoverdine level. The study of 23 partially characterized phenotypic clusters demonstrated that siderotyping is very useful in suggesting correlations between clusters and well-defined species and in detecting misclassified individual strains, as verified by DNA-DNA hybridization. The usefulness of siderotyping as a determinative tool was extended to the nonfluorescent species Pseudomonas corrugata, Pseudomonas frederiksbergensis, Pseudomonas graminis, and Pseudomonas plecoglossicida, which were seen to have an identical species-specific siderophore system and thus were easily differentiated from one another. Thus, the fast, accurate, and easy-to-perform siderotyping method compares favorably with the usual phenotypic and genomic methods presently necessary for accurate identification of pseudomonads at the species level.
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Xiao, Rong, and William S. Kisaalita. "Fluorescent Pseudomonad Pyoverdines Bind and Oxidize Ferrous Ion." Applied and Environmental Microbiology 64, no. 4 (April 1, 1998): 1472–76. http://dx.doi.org/10.1128/aem.64.4.1472-1476.1998.
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ABSTRACT Major pyoverdines from Pseudomonas fluorescens 2-79 (Pf-B), P. aeruginosa ATCC 15692 (Pa-C), and P. putida ATCC 12633 (Pp-C) were examined by absorption and fluorescence spectroscopic techniques to investigate the interaction between ferrous ion and the pyoverdine ligand. At physiological pH, ferrous ion quenched the fluorescence of all three pyoverdines much faster than ferric ion did. Also, increased absorbance at 460 nm was observed to be much faster for Fe2+-pyoverdine than for Fe3+-pyoverdine. At pH 7.4, about 90% of Fe3+was bound by pyoverdine Pa-C after 24 h whereas Fe2+was bound by the pyoverdine completely in only 5 min. The possibility that Fe2+ underwent rapid autoxidation before being bound by pyoverdine was considered unlikely, since the Fe2+concentration in pyoverdine-free samples remained constant over a 3-min period at pH 7.4. Incubating excess Fe2+ with pyoverdine in the presence of 8-hydroxyquinoline, an Fe3+-specific chelating agent, resulted in the formation of a Fe3+-hydroxyquinoline complex, suggesting that the iron in the Fe2+-pyoverdine complex existed in the oxidized form. These results strongly suggested that pyoverdines bind and oxidize the ferrous ion.
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Bultreys, Alain, Isabelle Gheysen, Bernard Wathelet, Henri Maraite, and Edmond de Hoffmann. "High-Performance Liquid Chromatography Analyses of Pyoverdin Siderophores Differentiate among Phytopathogenic Fluorescent Pseudomonas Species." Applied and Environmental Microbiology 69, no. 2 (February 2003): 1143–53. http://dx.doi.org/10.1128/aem.69.2.1143-1153.2003.
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ABSTRACT The relationship of pyoverdins produced by 41 pathovars of Pseudomonas syringae and by phytopathogenic Pseudomonas species was investigated. A high-performance liquid chromatography method for analyzing the culture medium proved to be superior to isoelectric focusing for detecting pyoverdin production, for differentiating slightly different pyoverdins, and for differentiating atypical from typical Fe(III)-chelated pyoverdins. Nonfluorescent strains were found in Pseudomonas amygdali, Pseudomonas meliae, Pseudomonas fuscovaginae, and P. syringae. Pseudomonas agarici and Pseudomonas marginalis produced typical pyoverdins. Among the arginine dihydrolase-negative fluorescent Pseudomonas species, spectral, amino acid, and mass spectrometry analyses underscored for the first time the clear similarities among the pyoverdins produced by related species. Within this group, the oxidase-negative species Pseudomonas viridiflava and Pseudomonas ficuserectae and the pathovars of P. syringae produced the same atypical pyoverdin, whereas the oxidase-positive species Pseudomonas cichorii produced a similar atypical pyoverdin that contained a glycine instead of a serine. The more distantly related species Pseudomonas asplenii and Pseudomonas fuscovaginae both produced a less similar atypical pyoverdin. The spectral characteristics of Fe(III)-chelated atypical pyoverdins at pH 7.0 were related to the presence of two β-hydroxyaspartic acids as iron ligands, whereas in typical pyoverdins one of the ligands is always ornithine based. The peptide chain influenced the chelation of iron more in atypical pyoverdins. Our results demonstrated that there is relative pyoverdin conservation in the amino acids involved in iron chelation and that there is faster evolution of the other amino acids, highlighting the usefulness of pyoverdins in systematics and in identification.
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Shirley, Matt, Laure Avoscan, Eric Bernaud, Gérard Vansuyt, and Philippe Lemanceau. "Comparison of iron acquisition from Fe–pyoverdine by strategy I and strategy II plants." Botany 89, no. 10 (October 2011): 731–35. http://dx.doi.org/10.1139/b11-054.
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Iron is an essential micronutrient for plants and associated microorganisms. However, the bioavailability of iron in cultivated soils is low. Plants and microorganisms have thus evolved active strategies of iron uptake. Two different iron uptake strategies have been described in dicotyledonous and monocotyledonous graminaceous species. In bacteria, this strategy relies on the synthesis of siderophores. Pyoverdines, a major class of siderophores produced by fluorescent pseudomonads, were previously shown to promote iron nutrition of the dicotyledonous species Arabidopsis thaliana L. (Heynh.), whereas contradictory reports were made on the contribution of those siderophores to the nutrition of graminaceous annuals. Furthermore, no information has so far been available on graminaceous perennials. Here, the contribution of purified pyoverdine of Pseudomonas fluorescens C7R12 to the iron nutrition of two annual and perennial graminaceous plants was assessed and compared with that of two dicotyledonous plant species. Fe–Pyoverdine promoted the iron status of all plant species tested. With the exception of wheat, this promotion was more dramatic in graminaceous species than in dicotyledonous species and was the highest in fescue, a perennial species. The incorporation of 15N-labeled pyoverdine was consistent with the effect on the iron status of the plants tested.
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Meyer, Jean-Marie, Christelle Gruffaz, Topi Tulkki, and Daniel Izard. "Taxonomic heterogeneity, as shown by siderotyping, of strains primarily identified as Pseudomonas putida." International Journal of Systematic and Evolutionary Microbiology 57, no. 11 (November 1, 2007): 2543–56. http://dx.doi.org/10.1099/ijs.0.65233-0.
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One hundred and forty-four fluorescent pseudomonad strains isolated from various environments (soil, water, plant rhizosphere, hospital) and received as Pseudomonas putida (83 strains), P. putida biovar A (49 strains), P. putida biovar B (10 strains) and P. putida biovar C (2 strains), were analysed by the pyoverdine-isoelectrofocusing and pyoverdine-mediated iron uptake methods of siderotyping. Both methods demonstrated a great diversity among these strains, which could be subdivided into 35 siderovars. Some siderovars specifically included strains that have subsequently been transferred to well-defined Pseudomonas species, e.g. Pseudomonas monteilii or Pseudomonas mosselii, or which could be related by their siderotype to Pseudomonas jessenii or Pseudomonas mandelii. Other siderovars included strains sharing a high level of DNA-DNA relatedness (>70 %), thus demonstrating that siderotyping could easily circumscribe strains at the species level. However, a group of seven strains, including the type strain, P. putida ATCC 12633T, were allocated into four siderovars, despite sharing DNA–DNA relatedness values of higher than 70 %. Interestingly, the strong genomic relationships between these seven strains were supported by the structural relationships among their pyoverdines, thus reflecting their phylogenetic affinities. These results strongly support the view that pyoverdine-based siderotyping could be used as a powerful tool in Pseudomonas taxonomy.
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Mohn, G., K. Taraz, and H. Budzikiewicz. "New Pyoverdin-Type Siderophores from Pseudomonas fluorescens." Zeitschrift für Naturforschung B 45, no. 10 (October 1, 1990): 1437–50. http://dx.doi.org/10.1515/znb-1990-1014.
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The structures of two new pyoverdins (GM-I and GM-II) isolated from the culture medium of Pseudomonas fluorescens have been elucidated by spectroscopic methods and degradation studies. The pyoverdins consist of a chromophore which could be identified as (1 S)-5-amino-2,3-dihydro-8,9-dihydroxy-1 H-pyrimido[1,2-a]quinoline-1-carboxylic acid substituted at the amino group with a 3-carboxypropanoyl or a succinamoyl residue and at the carboxy group with the N-terminus of D-Ala-D-Lys-Gly-Gly-D-threo-(OH)Asp-D-Glu-D-Ser-L-Ala-D-Ala-D-Ala-L-Ala-L-N5-(OH)Orn.According to the “short-hand” nomenclature proposed in [2]*** the two compounds should be characterized as pyoverdin-Q-akGGd'qsAaaAO′*-SUCA and pyoverdin-Q-akGGd'qsAaaAO′ *-SUC
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Rehm, Karoline, Vera Vollenweider, Rolf Kümmerli, and Laurent Bigler. "A comprehensive method to elucidate pyoverdines produced by fluorescent Pseudomonas spp. by UHPLC-HR-MS/MS." Analytical and Bioanalytical Chemistry 414, no. 8 (January 27, 2022): 2671–85. http://dx.doi.org/10.1007/s00216-022-03907-w.
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AbstractMicrobial secondary metabolites represent a rich source for drug discovery, plant protective agents, and biotechnologically relevant compounds. Among them are siderophores, iron-chelating molecules, that show a great influence on bacterial community assembly and the potential to control pathogen invasions. One of such a siderophore is pyoverdine that is produced by fluorescent Pseudomonas members and consists of different peptide chains specific to each bacterial species. The identification and structural elucidation of such suites of siderophores remain widely underexplored as general high-throughput analytical protocols are missing. Therefore, a dedicated method was established allowing a rapid localization and structural elucidation of pyoverdines. Liquid bacterial culture samples were purified by an easy small-scale solid-phase extraction (SPE). Ultra-high-performance liquid chromatography high-resolution tandem mass spectrometry (UHPLC-HR-MS/MS) separated highly polar pyoverdines and their derivatives. All ion fragmentation (AIF) generated mass spectra containing the characteristic fragments of the biological precursor of pyoverdine, ferribactin. This led to the revelation of the mass of secreted pyoverdines. Targeted MS/MS experiments at multiple collision energies accomplished the full structure elucidation of the pyoverdine peptide chain. A mass calculator and a fragmentation predictor facilitated greatly the interpretation of MS/MS spectra by providing accurate masses for a straightforward comparison of measured and theoretical values. The method was successfully validated using four well-known pyoverdines with various peptide chains. Finally, the applicability was proven by the analysis of 13 unknown pyoverdines secreted by sampled bacterial cultures. Among these, 4 novel pyoverdine peptide chains were discovered and are herein reported for the first time. Graphical abstract
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Inoue, Hiroyuki, Osamu Takimura, Ken Kawaguchi, Teruhiko Nitoda, Hiroyuki Fuse, Katsuji Murakami, and Yukiho Yamaoka. "Tin-Carbon Cleavage of Organotin Compounds by Pyoverdine from Pseudomonas chlororaphis." Applied and Environmental Microbiology 69, no. 2 (February 2003): 878–83. http://dx.doi.org/10.1128/aem.69.2.878-883.2003.
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ABSTRACT The triphenyltin (TPT)-degrading bacterium Pseudomonas chlororaphis CNR15 produces extracellular yellow substances to degrade TPT. Three substances (F-I, F-IIa, and F-IIb) were purified, and their structural and catalytic properties were characterized. The primary structure of F-I was established using two-dimensional nuclear magnetic resonance techniques; the structure was identical to that of suc-pyoverdine from P. chlororaphis ATCC 9446, which is a peptide siderophore produced by fluorescent pseudomonads. Spectral and isoelectric-focusing analyses revealed that F-IIa and F-IIb were also pyoverdines, differing only in the acyl substituent attached to the chromophore part of F-I. Furthermore, we found that the fluorescent pseudomonads producing pyoverdines structurally different from F-I showed TPT degradation activity in the solid extracts of their culture supernatants. F-I and F-IIa degraded TPT to monophenyltin via diphenyltin (DPT) and degraded DPT and dibutyltin to monophenyltin and monobutyltin, respectively. The total amount of organotin metabolites produced by TPT degradation was nearly equivalent to that of the F-I added to the reaction mixture, whereas DPT degradation was not influenced by monophenyltin production. The TPT degradation activity of F-I was remarkably inhibited by the addition of metal ions chelated with pyoverdine. On the other hand, the activity of DPT was increased 13- and 8-fold by the addition of Cu2+ and Sn4+, respectively. These results suggest that metal-chelating ligands common to pyoverdines may play important roles in the Sn-C cleavage of organotin compounds in both the metal-free and metal-complexed states.
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Amann, Cordula, Kambiz Taraz, Herbert Budzikiewicz, and Jean-Marie Meyer. "The Siderophores of Pseudomonas fluorescens 18.1 and the Importance of Cyclopeptidic Substructures for the Recognition at the Cell Surface." Zeitschrift für Naturforschung C 55, no. 9-10 (October 1, 2000): 671–80. http://dx.doi.org/10.1515/znc-2000-9-1001.
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Abstract The structure of the pyoverdin siderophore of Pseudomonas fluorescens 18.1 was elucidated by spectroscopic methods and chemical degradation. By cross feeding studies structurally closely related pyoverdins containing a C-terminal cyclopeptidic substructure were tested regarding the mutual recognition by the producing strains. Partial recognition of foreign pyoverdins was observed.
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Calcott, Mark J., Jeremy G. Owen, Iain L. Lamont, and David F. Ackerley. "Biosynthesis of Novel Pyoverdines by Domain Substitution in a Nonribosomal Peptide Synthetase of Pseudomonas aeruginosa." Applied and Environmental Microbiology 80, no. 18 (July 11, 2014): 5723–31. http://dx.doi.org/10.1128/aem.01453-14.
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ABSTRACTPyoverdine is a fluorescent nonribosomal peptide siderophore made by fluorescent pseudomonads. ThePseudomonas aeruginosanonribosomal peptide synthetase (NRPS) PvdD contains two modules that each incorporate anl-threonine residue at the C-terminal end of pyoverdine. In an attempt to generate modified pyoverdine peptides, we substituted alternative-substrate-specifying adenylation (A) and peptide bond-catalyzing condensation (C) domains into the second module of PvdD. When just the A domain was substituted, the resulting strains produced only wild-type pyoverdine—at high levels if the introduced A domain specified threonine or at trace levels otherwise. The high levels of pyoverdine synthesis observed whenever the introduced A domain specified threonine indicated that these nonnative A domains were able to communicate effectively with the PvdD C domain. Moreover, the unexpected observation that non-threonine-specifying A domains nevertheless incorporated threonine into pyoverdine suggests that the native PvdD C domain exhibited stronger selectivity than these A domains for the incorporated amino acid substrate (i.e., misactivation of a threonine residue by the introduced A domains was more frequent than misincorporation of a nonthreonine residue by the PvdD C domain). In contrast, substitution of both the C and A domains of PvdD generated high yields of rationally modified pyoverdines in two instances, these pyoverdines having either a lysine or a serine residue in place of the terminal threonine. However, C-A domain substitution more commonly yielded a truncated peptide product, likely due to stalling of synthesis on a nonfunctional recombinant NRPS template.
Dissertations / Theses on the topic "Pyoverdine Pseudomonas fluorescen"
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Folschweiller, Nicolas. "Etudes structurales du recepteur de la Pyoverdine FpvA de Pseudomonas aeruginosa." Université Louis Pasteur (Strasbourg) (1971-2008), 2002. http://www.theses.fr/2002STR13187.
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Etudes Structurales du Recepteur de la Pyoverdine FpvA de Pseudomonas aeruginosa. Pseudomonas aeruginosa est une bactérie pathogène impliquée dans 10 à 20 % des infections nosocomiales. Ses cibles privilégiées sont les malades immuno-déficients, ceux atteints de mucoviscidose et les grands brûlés. L'un de ses deux principaux systèmes d'incorporation du fer, qui est en partie responsable dans son grand pouvoir infectieux est basé sur la pyoverdine PaA et son récepteur de membrane externe FpvA, un récepteur TonB-dépendant. Ce travail s'est attaché à mieux comprendre les interactions hautement spécifiques entre la pyoverdine et FpvA. Dans une première partie, une étude des séquences de nombreux récepteurs TonB dépendants disponibles dans les banques de données a été réalisée, afin de mieux caractériser le récepteur FpvA. Les possibilités de transfert d'énergie de résonance de Förster (FRET) entre le récepteur et son ligand sont également présentées. Dans une deuxième partie, les interactions récepteur-ligand dans les différents complexes formés in vivo et in vitro du couple pyoverdine-FpvA sont étudiés par la technique de fluorescence résolue dans le temps, afin de mieux comprendre les moyens qu'utilise la bactérie pour différencier ces complexes et internaliser celui dont elle a besoin. Dans une troisième partie, un protocole rapide et efficace de purification à partir de la surexpression homologue de FpvA est présenté. Les expériences de cristallogenèse tridimensionnelles réalisées à la suite aboutissent à plusieurs formes cristallines dont les plus performantes montrent une diffraction jusqu'à 2,7 Å à basse températureStructural Studies of the Pyoverdin Receptor FpvA from Pseudomonas aeruginosa. Pseudomonas aeruginosa is a gram negative bacteria involved in 10 to 20 % of hospitals infections. Its main targets are burnt and immuno-deficient patients, and people who have developped a cystic fibrosis disease. Its major iron acquisition system also involved in its infectious capacity, is based upon the pyoverdin PaA and its outer membrane receptor FpvA, a TonB dependant receptor. This thesis work intend to better understand the highly specific interactions between the pyoverdin and FpvA. In the first part, we studied many sequences of TonB-dependant receptors available in data banks, in order to identify importants regions of the proteins. The Förster resonnance energy transfer (FRET) abilities between the receptor and its ligand are also presented. In the second part, we used the time-resolved fluorescence spectroscopy technique to study the receptor-ligand interactions of the different FpvA-PaA in vivo and in vitro made complexes. The aim of this work is to understand how the bacteria makes a difference between all these complexes and translocates only the PaA-Iron one. In the third part, we established an efficient and fast process for the FpvA purification from the homologous over expression system in Pseudomonas aeruginosa. We started the 3D crystallogenesis experiments in order to resolve the 3D structure of the FpvA-PaA in vivo made complex. We obtained crystals diffracting at up to 2. 7 A at low temperature
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CHIADO', ALESSANDRO. "Evaluation of new biorecognition elements for environmental monitoring." Doctoral thesis, Politecnico di Torino, 2013. http://hdl.handle.net/11583/2511708.
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To date, environmental monitoring is mainly focused on traditional chemical techniques, or on the assessment of specific biomarkers. However, these analyses are affected by several limitations: mainly, they are expensive, spot-sampling and time-consuming. In order to overcome these drawbacks, new biological monitoring methods, such as biosensors and biological early warning system (BEWS) are under development. These kinds of devices, built around whole cells, enzymes and antibodies, are well-suited to cooperatively and continuously monitor the environmental conditions. The key-factor of this very promising approach is the biological sensing element. Whole cell systems and enzymes are well suited for environmental monitoring: they are able to determine the bioavailable and toxic concentration of xenobiotics, especially if the source and nature of the compound cannot be predicted. Microorganisms usually detect a broad spectrum of chemicals, and represent a good opportunity for low cost, long shelf-life, and wide range of conditions in which they can be applied. Besides, enzymes are effective when a particular kind of pollutant would be detected because is possible to fine tune their metabolic behaviour by means of protein engineering.
In this work, three biological sensing elements, related to three different index of toxicity were evaluated, in order to develop new biosensors for environmental monitoring: a broad toxicity index associated to the decrease of light emission (EC50 or half effective concentration) of a bioluminescent bacterium, Vibrio fischeri, a metal toxicity connected to the metal-regulated production of a siderophore (pyoverdine) by the soil and water microorganism Pseudomonas fluorescens, and finally an index of toxicity given by PAHs, was related to the metabolization of these compounds by laccase of Trametes versicolor.
One of the first step during the assessment of a new biological sensing element is the study of the effect of physical-chemical parameters. The tested physical-chemical parameters (temperature, pH, inoculum percentage (v/v) and carbon source) influenced both microbial sensible elements (V. fischeri and P. fluorescens), therefore, these sensible elements can be used in a whole-cell biosensor for in-situ application, even if the response is affected by the environmental variables. Furthermore, the light emission of V. fischeri was highly variable, although a more stable bioluminescence was obtained by means of a glucose fed-batch: this is one step towards the direct application of this system, usually tailored for laboratory assays, to estimate the broad acute toxicity directly in situ in a portable device.
Regarding the interaction between P. fluorescens and Fe3+, Cu2+, and Zn2+, the minimum inhibitory concentration (MIC) and the pyoverdine critical concentration (PCC) obtained values were compared to those indicated in the WHO Guidelines for drinking water quality and in European directive 98/83/EC: MICs of Fe3+, Cu2+ and Zn2+ are always above the threshold specified, whilst PCCs are very near to the recommended thresholds for iron and copper. The PCC was not determined for zinc in the tested range of concentration and conditions. These results highlighted that this sensible element should be further investigated for the development of a biosensor able to monitor metals in the environment.
The last and most promising sensing element assessed in this work was the lccβ laccase of T. versicolor. A combination of computational docking (SwissDock) and molecular biology techniques was used to generate rationally engineered laccases with increased ability to process large and persistent PAHs. These mutated isoforms were produced by heterologous expression in P. pastoris, successfully purified, and characterized by means of biochemical assays. The activity of the enzymes was initially tested and characterized with phenolic and non phenolic substrates at different pH (3.0-8.0): the best mutated enzyme F162A/L164A (M1) showed an increased specific activity (UI/mg) in comparison with the wild type, in every tested condition. This result was in agreement with those obtained by computational docking simulations (estimated free binding energy), validating the rational design approach.
Moreover, decolourization assays of large aromatic dyes, used as model compounds, have shown that the mutated enzymes are reactive towards molecules with chemical structure resembling that of aromatic organic pollutants. By means of example, enzyme mutants with a larger binding pocket (e.g. M1) showed higher activity against triphenylmethane dyes (e.g. Methyl Green), especially without a mediator of the reaction (HBT), and high stability under a variety of temperature conditions (4, 22 °C, room temperature). Therefore, the best enzyme should be integrated on an appropriate transducer (e.g. electrode), and coupled to a wireless platform generating a BEWS for environmental monitoring.
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Mirleau, Pascal. "Rôle de la pyoverdine et de la nitrate réductase dans la compétence rhizosphérique et tellurique de la souche de Pseudomonas fluorescens C7R12." Dijon, 2000. http://www.theses.fr/2000DIJOS034.
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Les Pseudomonas spp. Fluorescents sont impliqués dans la résistance naturelle de certains sols à des maladies d'origine tellurique. Ils sont considérés comme des agents potentiels de lutte biologique. L'efficacité de cette lutte fait défaut pour les plantes cultivées en sol. Le manque de fiabilité de la protection des cultures de plein champ a en particulier été attribué à la mauvaise survie des Pseudomonas spp. Fluorescents dans la rhizosphère des plantes inoculées. Des études visant à identifier les caractères microbiens impliqués dans l'adaptation à la rhizosphère des Pseudomonas spp. Fluorescents ont donc été entreprises. Les études de diversité conduites précédemment au laboratoire suggèrent que l'aptitude à mobiliser le fer ferrique et à dissimiler les oxydes d'azote sont impliquées dans la compétence rhizosphérique des Pseudomonas spp. Fluorescents. L'objectif de ce mémoire concerne la dernière etape de l'approche populationnelle entreprise, à savoir : le développement et l'utilisation des outils nécessaires pour vérifier l'implication de ces caractères dans l'adaptation à la rhizosphère. La souche Pseudomonas fluorescens C7R12 a été choisie comme modèle bactérien en raison de (i) son efficacité en lutte biologique, (ii) sa bonne survie dans la rhizosphère, (iii) sa forte aptitude à mobiliser le fer et (iv) sa capacité a dissimiler les oxydes d'azote. La stratégie adoptée a consisté à (i) définir des méthodes de mutagenèse en fonction des connaissances disponibles sur les deux caractères bactériens à altérer, (ii) a caractériser les fonctions affectées par la mutagenèse et (iii) à évaluer, par des études de compétitivité, l'implication des fonctions altérées dans l'adaptation à la rhizosphère de C7R12. Dans ce mémoire, nous décrivons successivement (i) l'obtention et la caractérisation génétique de mutants de C7R12 affectés dans l'aptitude à mobiliser le fer ferrique et/ou a dissimiler les nitrates (chapitre i), (ii) la caractérisation physiologique des mutants obtenus (chapitre ii) et (iii) la compétitivité comparée des mutants et de la souche sauvage dans le sol nu et la rhizosphère (chapitre iii). Les méthodes de mutagenèse appliquées ont permis l'obtention de mutants affectés dans la synthèse et l'incorporation de pyoverdine et/ou dans la synthèse de nitrate réductase. Les principaux résultats acquis confirment du rôle de la pyoverdine et de la nitrate réductase dans la compétence rhizosphérique mais également tellurique de C7R12. L'avantage compétitif conféré par la nitrate réductase s'exprime principalement en conditions peu aérées. Globalement, ces résultats suggèrent que la compétence saprophyte de C7R12 est en partie associée à son aptitude à utiliser alternativement comme accepteurs finaux d'électrons l'oxygène et les nitrates. Par ailleurs, ce travail a permis de séquencer une partie du gène codant une peptide synthétase impliquée dans la synthèse de pyoverdine.
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Trapet, Pauline. "Incidence physiologique et étude du mode d'action de la pyoverdine de Pseudomonas fluorescens chez Arabidopsis thaliana : liens avec l'homéostasie du fer, la croissance et les défenses." Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS053/document.
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Ce travail s’inscrit dans l’étude de l’incidence de sidérophores sur la physiologie de la plante. Il décrit plus précisément, à l’échelle phénotypique et moléculaire, l’impact de la pyoverdine produite par la souche bactérienne bénéfique Pseudomonas fluorescens C7R12 sur la croissance, la réponse immunitaire et l’homéostasie du fer chez Arabidopsis thaliana. Le lien fonctionnel entre immunité et homéostasie du fer a été abordé de façon plus spécifique via l’analyse du mode d’action de l’acide β-aminobutyrique (BABA), un potentialisateur des réponses de défense de la plante. En conditions de fer limitantes, afin de pourvoir à la carence, Pseudomonas fluorescens libère la pyoverdine dans le sol sous sa forme non chélatée (apo-pyo). Le complexe fer-pyoverdine (ferri-pyo) est ensuite internalisé par la bactérie. Nous avons vérifié que l’apo-pyo est assimilée par des plantes d’A. thaliana cultivées dans un milieu contenant ou non du fer. De façon remarquable, l’apo-pyo restaure le phénotype de croissance des plantes carencées en fer. Une analyse transcriptomique a révélé que chez ces dernières, l’apo-pyo induit fortement l’expression de gènes associés à la croissance, l’import et la redistribution du fer in planta. En revanche, une répression de l’expression de gènes de défense s’opère. De façon concordante, l’effet promoteur de croissance de l’apo-pyo chez les plantes carencées est strictement dépendant de l’expression des gènes IRT1 et FRO2 codant deux protéines majeures de l’import de fer. De plus, une moindre résistance de ces plantes à Botrytis cinerea a été relevée. L’incidence négative de l’apo-pyo sur les défenses s’accompagne d’une surexpression du facteur de transcription HBI1 jouant un rôle clé dans la régulation de la balance croissance/défense. L’ensemble de ces événements n’a pas été observé chez les plantes cultivées dans un milieu enrichi en fer, démontrant que les effets de l’apo-pyo chez A. thaliana sont conditionnés par le statut en fer de la plante. En parallèle, l’étude du mode d’action du BABA a indiqué que ce potentialisateur de l’immunité est un chélateur très efficace du fer. En conséquence, appliqué à des plantes d’A. thaliana, le BABA déclenche une carence en fer transitoire. Nous avons émis l’hypothèse que cette carence pourrait constituer un signal plaçant la plante en veille défensive. En accord avec cette assomption, les plantes carencées en fer présentent une résistance accrue à B. cinerea et produisent des métabolites secondaires associés aux défenses dont l’accumulation est également induite par le BABA. Ainsi, la carence en fer transitoire occasionnée par le BABA pourrait constituer l’une des composantes de son effet potentialisateur sur l’immunité. En conclusion, ce travail apporte des premiers éléments explicatifs quant à l’incidence de la pyoverdine sur des traits physiologiques de la plante et rapporte un mode d’action orignal du BABA. Plus généralement, il renforce le concept encore naissant de l’existence de régulations croisées entre les voies de signalisation associées à la croissance, l’immunité et l’homéostasie du fer chez les plantesSiderophores are strong iron chelators produced by bacteria under iron deficiency conditions. In the present work, we studied the impact of the siderophore pyoverdine, produced by the plant growth promoting rhizobacteria Pseudomonas fluorescens C7R12, on plant physiology from phenotypic to molecular effects with a specific focus on plant growth, immune response and iron homeostasis. Based on our analysis of the mode of action of the non-protein amino acid β-aminobutyric acid (BABA), a priming inducer in plants, we studied more specifically the functional link between iron homeostasis and plant immunity. Under iron deficiency, P. fluorescens excretes the iron free form of pyoverdine (apo-pyo) in the soil. Once chelated with iron (ferri-pyo), the complex is internalized by the bacteria. We demonstrated that Arabidopsis thaliana plants treated by apo-pyo in a medium containing or not iron (Fe 25 or Fe 0) also internalize pyoverdine. Moreover, we observed that under iron deficiency, pyoverdine treated plants did not display the growth reduction induced by iron deficiency. In accordance with this phenotype, a microarray analysis revealed that the expression of genes related to growth and development was induced, as well as genes related to iron uptake and transport in planta. In contrast, the down regulation of the expression of genes related to defense was observed. Correspondingly, we demonstrated that the growth improvement induced by apo-pyo under iron deficiency depends on the expression of IRT1 and FRO2, two major genes involved in iron uptake mechanisms. Of interest, the resistance to Botrytis cinerea conferred by iron deficiency was lost following apo-pyo treatment. The overexpression of the HBI1 transcription factor, known to be involved in the growth-defense tradeoff, can be linked to the above observations. These apo-pyo effects were not observed after treatment of plants under sufficient iron conditions, indicating that in A. thaliana apo-pyo effects are dependent on the plant iron status. In the same time, the analysis of the mode of action of BABA that potentiates plant defense responses demonstrated that BABA is a powerful iron chelator. BABA treatment in A. thaliana triggered a transient iron deficiency response. Based on this assessment, we assume that iron deficiency response and priming of defense may be connected. In accordance with this hypothesis, we showed that plants cultivated under iron deficiency and BABA treated plants both displayed resistance to B. cinerea and produced secondary metabolites associated to defense. Hence, the BABA priming effects on plant defense may be due to the induction of transient iron deficiency. To conclude, this work draws first explications on pyoverdine effects on plant physiology and presents an original mode of action contributing to the priming effects of BABA. In a larger view, this work supports the recent concept of the existence of a cross-regulation between growth, immunity and iron homeostasis in plants
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David, Sébastien. "Altération de déchets amiantés par des bactéries et des sidérophores en vue du développement d’un procédé de bioremédiation." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAJ087.
Full textAbstract:
Compte tenu de ses effets néfastes sur la santé, l’amiante est interdit en France depuis 1997, entrainant la gestion de tonnages importants de déchets. Les seules méthodes actuelles sont l’enfouissement ou la vitrification par la technologie plasma. L’objectif de ce projet de recherche était d’explorer diverses voies biologiques afin de développer un procédé biotechnologique permettant le traitement de déchets amiantés. Ce travail a permis de démontrer la capacité des pyoverdines à solubiliser le fer présent dans les amiantes avec des efficacités variables selon leur structure. Nous avons mis en évidence que les Pseudomonas fluorescents sont capables de puiser dans les déchets le fer grâce à l’utilisation des sidérophores mais également du magnésium par un mécanisme restant à déterminer. De plus, des acides organiques en présence de bactéries a permis l’extraction d’une grande quantité de fer et de magnésium présente dans les déchets d’amiantes qui semble la plus prometteuseConsidering its toxic effect on health, the use of asbestos has been banned in France since 1997. Currently, asbestos removal is a priority and we have to deal with huge amount of wastes. Only two treatments are in use, storage or transformation in glass by plasma technology. However, these methods do not eliminate the waste. The aim of this project is to explore various biological pathways in order to develop a biotechnical process to treat asbestos waste. This work showed for the first time that pyoverdines are able to solubilize iron from asbestos with various efficiency depending in pyoverdine structure. We highlighted that waste represent an iron and magnesium source for fluorescent Pseudomonas thanks to the use of siderophores for iron release and an unknown mechanism for magnesium. Moreover, the use of organic acids associated with bacteria allowed a huge extraction of iron and magnesium from asbestos waste, which is the best pathway to date
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Demange, Pascal. "Siderophores bacteriens : structure de pyoverdines et de composes apparentes." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13163.
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Glorius, M., H. Moll, G. Bernhard, A. Roßberg, and A. Barkleit. "The Mobilization of Actinides by Microbial Ligands Taking into Consideration the Final Storage of Nuclear Waste - Interactions of Selected Actinides U(VI), Cm(III), and Np(V) with Pyoverdins Secreted by Pseudomonas fluorescens and Related Model Compounds (Final Report BMBF Project No.: 02E9985)." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-27809.
Full textAbstract:
The groundwater bacterium Pseudomonas fluorescens (CCUG 32456) isolated at a depth of 70 m in the Äspö Hard Rock Laboratory secretes a pyoverdin-mixture with four main components (two pyoverdins and two ferribactins). The dominant influence of the pyoverdins of this mixture could be demonstrated by an absorption spectroscopy study. The comparison of the stability constants of U(VI), Cm(III), and Np(V) species with ligands simulating the functional groups of the pyoverdins results in the following order of complex strength: pyoverdins (PYO) > trihydroxamate (DFO) > catecholates (NAP, 6HQ) > simple hydroxamates (SHA, BHA). The pyoverdin chromophore functionality shows a large affinity to bind actinides. As a result, pyoverdins are also able to complex and to mobilize elements other than Fe(III) at a considerably high efficiency. It is known that EDTA may form the strongest actinide complexes among the various organic components in nuclear wastes. The stability constants of 1:1 species formed between Cm(III) and U(VI) and pyoverdins are by a factor of 1.05 and 1.3, respectively, larger compared to the corresponding EDTA stability constants. The Np(V)-PYO stability constant is even by a factor of 1.83 greater than the EDTA stability constant. The identified Np(V)-PYO species belong to the strongest Np(V) species with organic material reported so far. All identified species influence the actinide speciation within the biologically relevant pH range. The metal binding properties of microbes are mainly determined by functional groups of their cell wall (LPS: Gram-negative bacteria and PG: Gram-positive bacteria). On the basis of the determined stability constants raw estimates are possible, if actinides prefer to interact with the microbial cell wall components or with the secreted pyoverdin bioligands. By taking pH 5 as an example, U(VI)-PYO interactions are slightly stronger than those observed with LPS and PG. For Cm(III) we found a much stronger affinity to aqueous pyoverdin species than to functional groups of the cell wall compartments. A similar behavior was observed for Np(V). This shows the importance of indirect interaction processes between actinides and bioligands secreted by resident microbes.
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Glorius, M., H. Moll, G. Bernhard, A. Roßberg, and A. Barkleit. "The Mobilization of Actinides by Microbial Ligands Taking into Consideration the Final Storage of Nuclear Waste - Interactions of Selected Actinides U(VI), Cm(III), and Np(V) with Pyoverdins Secreted by Pseudomonas fluorescens and Related Model Compounds (Final Report BMBF Project No.: 02E9985)." Forschungszentrum Dresden-Rossendorf, 2009. https://hzdr.qucosa.de/id/qucosa%3A21603.
Full textAbstract:
The groundwater bacterium Pseudomonas fluorescens (CCUG 32456) isolated at a depth of 70 m in the Äspö Hard Rock Laboratory secretes a pyoverdin-mixture with four main components (two pyoverdins and two ferribactins). The dominant influence of the pyoverdins of this mixture could be demonstrated by an absorption spectroscopy study. The comparison of the stability constants of U(VI), Cm(III), and Np(V) species with ligands simulating the functional groups of the pyoverdins results in the following order of complex strength: pyoverdins (PYO) > trihydroxamate (DFO) > catecholates (NAP, 6HQ) > simple hydroxamates (SHA, BHA). The pyoverdin chromophore functionality shows a large affinity to bind actinides. As a result, pyoverdins are also able to complex and to mobilize elements other than Fe(III) at a considerably high efficiency. It is known that EDTA may form the strongest actinide complexes among the various organic components in nuclear wastes. The stability constants of 1:1 species formed between Cm(III) and U(VI) and pyoverdins are by a factor of 1.05 and 1.3, respectively, larger compared to the corresponding EDTA stability constants. The Np(V)-PYO stability constant is even by a factor of 1.83 greater than the EDTA stability constant. The identified Np(V)-PYO species belong to the strongest Np(V) species with organic material reported so far. All identified species influence the actinide speciation within the biologically relevant pH range. The metal binding properties of microbes are mainly determined by functional groups of their cell wall (LPS: Gram-negative bacteria and PG: Gram-positive bacteria). On the basis of the determined stability constants raw estimates are possible, if actinides prefer to interact with the microbial cell wall components or with the secreted pyoverdin bioligands. By taking pH 5 as an example, U(VI)-PYO interactions are slightly stronger than those observed with LPS and PG. For Cm(III) we found a much stronger affinity to aqueous pyoverdin species than to functional groups of the cell wall compartments. A similar behavior was observed for Np(V). This shows the importance of indirect interaction processes between actinides and bioligands secreted by resident microbes.
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Hartney, Sierra Louise 1980. "TonB-dependent outer-membrane proteins of Pseudomonas fluorescens : diverse and redundant roles in iron acquisition." Thesis, 2011. http://hdl.handle.net/1957/26465.
Full textAbstract:
Pseudomonas is a diverse genus of Gram-negative bacteria that includes pathogens of plants, insects, and humans as well as environmental strains with no known pathogenicity. Pseudomonas fluorescens itself encompasses a heterologous group of bacteria that are prevalent in soil and on foliar and root surfaces of plants. Some strains of P. fluorescens suppress plant diseases and the genomic sequences of many biological control strains are now available. I used a combination of bioinformatic and phylogenetic analyses along with mutagenesis and biological assays to identify and compare the TonB-dependent outer-membrane proteins (TBDPs) of ten plant-associated strains of P. fluorescens and related species. TBDPs are common in Gram-negative bacteria, functioning in the uptake of ferric-siderophore complexes and other substrates into the cell. I identified 14 to 45 TBDRs in each strain of P. fluorescens or P. chlororaphis. Collectively, the ten strains have 317 TBDPs, which were grouped into 84 types based upon sequence similarity and phylogeny. As many as 13 TBDPs are unique to a single strain and some show evidence of horizontal gene transfer. Putative functions in the uptake of diverse groups of microbial siderophores, sulfur-esters, and other substrates were assigned to 28 of these TBDP types based on similarity to characterized orthologs from other Pseudomonas species. Redundancy of TBDP function was evident in certain strains of P. fluorescens, especially Pf-5, which has three TBDPs for ferrichrome/ferrioxamine uptake, two for ferric-citrate uptake and three for heme uptake.
Five TBDP types are present in all ten strains, and putative functions in heme, ferrichrome, cobalamin, and copper/zinc uptake were assigned to four of the conserved TBDPs.
The fluorescent pseudomonads are characterized by the production of pyoverdine siderophores, which are responsible for the diffusible UV fluorescence of these bacteria. Each of the ten plant-associated strains of P. fluorescens or P. chlororaphis has three to six TBDPs with putative roles in ferric-pyoverdine uptake (Fpv). To confirm the roles of the six Fpv outer membrane proteins in P. fluorescens Pf-5, I introduced deletions into each of the six fpv genes in this strain and evaluated the mutants and the parental strain for heterologous pyoverdine uptake. I identified at least one ferric-pyoverdine that was taken up by each of the six Fpv outer-membrane proteins of Pf-5. By comparing the ferric-pyoverdine uptake assay results to a phylogenetic analysis of the Fpv outer-membrane proteins, I observed that phylogenetically-related Fpv outer-membrane proteins take up structurally-related pyoverdines. I then expanded the phylogenetic analysis to include nine other strains within the P. fluorescens group, and identified five additional types of Fpv outer-membrane proteins. Using the characterized Fpv outer-membrane proteins of Pf-5 as a reference, pyoverdine substrates were predicted for many of the Fpv outer-membrane proteins in the nine other strains. Redundancy of Fpv function was evident in Pf-5, as some pyoverdines were recognized by more than one Fpv. It is apparent that heterologous pyoverdine recognition is a conserved feature, giving these ten strains flexibility in acquiring iron from the environment.
Overall, the TBDPs of the P. fluorescens group are a functionally diverse set of structurally-related proteins present in high numbers in many strains. While putative functions have been assigned to a subset of the proteins, the functions of most TBDPs remain unknown, providing targets for further investigations into nutrient uptake by P. fluorescens spp.. The work presented here provides a template for future studies using a combination of bioinformatic, phylogenetic, and molecular genetic approaches to predict and analyze the function of these TBDPs.Graduation date: 2012
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Cowie, Erin. "The influence of iron concentration on the production of pyoverdine by Pseudomonas aeruginosa in mono and mixed biofilm cultures." Thesis, 2018. http://hdl.handle.net/1959.7/uws:52076.
Full textAbstract:
Most species of bacteria have the ability to form biofilms, communities of bacterial cells that aggregate in a self-made matrix of extracellular polymeric substances (EPS), that allow them to adhere to inert and organic substances (Banin, Vasil and Greenberg, 2005; Lin et al., 2012). The biofilm is perceived to be the dominant form of bacterial life in the environment (Donlan and Costerton, 2002) and in comparison to planktonic or free swimming cells, sessile or biofilm cells often have a higher tolerance to antibiotics and host defense mechanisms, alluding to their importance in human health and disease (Hentzer, Eberl and Givskov, 2005). One of the many factors regulating biofilm growth and formation is the presence or absence of iron (Lin et al., 2012). Iron is an essential nutrient for growth, in order to acquire iron many bacteria produce siderophores to sequester iron from host proteins and the environment (Rédly and Poole, 2003). Pyoverdine (PVD) is one of two hydroxamate classed siderophores produced by P. aeruginosa (Meyer et al., 1997; Schalk et al., 2001) and regulated in part by Fur (Imperi, Banin). While iron concentration, pyoverdine production and biofilm formation have been studied in relation to P. aeruginosa, studies of this complex relationship has not yet been conducted in relation to mixed cultures. The aim of this research was to study the influence of iron concentration on the production of pyoverdine by Psuedomonas aeruginosa in mono and mixed biofilm cultures with Staphylococcus aureus Newman strain. An iron assay kit determined the concentration of iron in 1% TSB to be 1.62μM. Pyoverdine levels in P. aeruginosa biofilms were higher in 0.1% TSB biofilms than 1% TSB biofilms. In planktonic growth, pyoverdine concentration was higher in 1% TSB. Crystal violet assays were used to determine the biofilm forming capabilities of P. aeruginosa and S. aureus Newman in differing iron conditions. P. aeruginosa formed more biofilm in 1% TSB, and formed more biofilm than S. aureus Newman in both media. S. aureus, surprisingly, formed more biofilm in 1% TSB as opposed to 0.1%TSB regardless of the fact that S. aureus Newman was been proven to promote biofilm formation only in low iron environments (Johnson, Cockayne and Morrissey, 2008; Lin et al., 2012). The amount of CFU of bacteria in mixed cultures was determined through sonicating biofilm cells into buffer and spread plating. P. aeruginosa dominated the biofilm growth in all 0.1% TSB mixed biofilms, however in 1% TSB mixed culture, S. aureus Newman produced more biofilm than P. aeruginosa when inoculated first. Due to interference within the co-cultures, the pyoverdine levels within the mixed culture biofilms were not established. Further investigation of pyoverdine concentrations in mixed culture biofilms of different iron concentrations would allow for a better understanding of the complex interrelationship between pyoverdine production, biofilm formation and iron concentration. Three factors that contribute significantly to the bacteria’s ability to cause infection and mortality.
Book chapters on the topic "Pyoverdine Pseudomonas fluorescen"
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Hohnadel, D., and J. M. Meyer. "Pyoverdine-Facilitated Iron Uptake Among Fluorescent Pseudomonads." In Iron, Siderophores, and Plant Diseases, 119–29. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4615-9480-2_14.
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Meyer, Jean-Marie, and Valérie A. Geoffroy. "Environmental Fluorescent Pseudomonas and Pyoverdine Diversity: How Siderophores Could Help Microbiologists in Bacterial Identification and Taxonomy." In Iron Transport in Bacteria, 451–68. Washington, DC, USA: ASM Press, 2014. http://dx.doi.org/10.1128/9781555816544.ch29.
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Lemanceau, Philippe, Agnès Robin, Sylvie Mazurier, and Gérard Vansuyt. "Implication of Pyoverdines in the Interactions of Fluorescent Pseudomonads with Soil Microflora and Plant in the Rhizosphere." In Soil Biology, 165–92. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71160-5_8.
Full textConference papers on the topic "Pyoverdine Pseudomonas fluorescen"
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Deweever, A., S. S. Subedi Paudel, R. Balczon, T. Stevens, and Center for Lung Biology. "Untangling the Fluorescence Behavior of Pulmonary Amyloids and Pseudomonas Aeruginosa's Siderophore Pyoverdine." In American Thoracic Society 2021 International Conference, May 14-19, 2021 - San Diego, CA. American Thoracic Society, 2021. http://dx.doi.org/10.1164/ajrccm-conference.2021.203.1_meetingabstracts.a2894.
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