Siderophores of the Pseudomonadaceae sensu stricto (fluorescent and non-fluorescent Pseudomonas spp.).
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Agriculture↗
Biomedical subjects
H Budzikiewicz
Publications and source records attributed to H Budzikiewicz.
Heteroaromatic monothiocarboxylic acids from Pseudomonas spp.
Pyridine derivatives substituted with monothiocarboxylic acid groups are the unique metabolites of certain Pseudomonas species. Pyridine-2,6-di-(monothiocarboxylic acid) 1a was found during a screening program for antibiotically active bacterial metabolites due to its ability to complex Fe3+. The structure of this complex, its redox behavior and the biogenesis of the ligand molecule were studied in detail. This lead to the discovery of a new class of natural products, viz. acylsulfenic acid derivatives. Interest in la was revived shortly when complexes with other metals were studied as models for sulfur-containing enzymes. It could also be shown that a quinoline monothiocarboxylic acid derivative acted as an alternative siderophore for Pseudomonas fluorescens. But a real renaissance was observed only when the role of la in the degradation of CCl4 by Pseudomonas stutzeri became evident.
Biodegradation, Environmental↗
Fluorescent Pseudomonas mainly produce the dihydro form of pyoverdine at low specific growth rate.
AIMS: To analyse the influence of cell growth rate and iron concentration on the production of pyoverdines (PVDs) and of their reduced dihydro forms by three fluorescent Pseudomonas strains (P. putida BTP16, P. fluorescens BTP7 and P. aeruginosa 7NSK2). METHODS: PVD and dihydropyoverdine (DHPVD) productions were determined by LC ESI-MS and spectrophotometry during batch and chemostat culture at different dilution rates. SIGNIFICANCE: The relatively high PVD-to-DHPVD ratio (0.57) observed in pH-controlled batch cultures suggested that a base-catalysed chemical oxidation of the dihydroform is not the prime mechanism involved in generating PVDs. Interestingly, in chemostat cultures the PVD-to-DHPVD ratio was significantly reduced at low specific growth rate. Our results suggest that the oxidation of DHPVD to PVD is catalysed by an iron-dependent enzymatic reaction rather than a chemical oxidation.
Biomass↗
In-gel deglycosylation of sodiumdodecyl sulfate polyacrylamide gel electrophoresis-separated glycoproteins for carbohydrate estimation by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
Mass determination by mass spectrometric methods (electrospray ionization mass spectrometry (ESI-MS), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS)) of sodiumdodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE)-separated proteins is a well known procedure and reliable protocols are available. In our efforts to use the established methods to determine the molecular mass of the disulfide bridged, heterodimeric glycoprotein GP3 and to determine the carbohydrate content of each protein subunit we developed an in-gel chemical deglycosylation method. For this purpose we established experimental conditions that allow maximum extraction of the high molecular mass protein subunits and developed a routine method to apply the HF-pyridine deglycosylation protocol to proteins isolated from polyacrylamide gel pieces. The novel protocol and extraction procedure described can be used to analyze O-glycosylated proteins up to 150 kDa after SDS-PAGE separation.
Animals↗
Chalconoid and stilbenoid glycosides from Guibourtia tessmanii.
Phytochemical studies on the stem bark of Guibourtia tessmanii yielded a dihydrochalcone glucoside, 2',4-dihydroxy-4'-methoxy-6'-O-beta-glucopyranoside dihydrochalcone and a new stilbene glycoside, 3,5-dimethoxy-4'-O-(beta-rhamnopyranosyl-(1-->6)-beta- glucopyranoside) stilbene besides the known pterostilbene. Their structures were established on the basis of one and two dimensional NMR spectroscopic techniques, FABMS and chemical evidence.
Chalcone↗
A fast atom bombardment and matrix-assisted laser desorption/ionization mass spectrometry study of doubly charged porphyrins.
In this mass spectrometry (MS) study of doubly charged porphyrin salts, fast atom bombardment (FAB) and matrix-assisted laser desorption/ionization (MALDI) MS techniques are utilized to examine several unique ionic species. The predominant transformation of preformed doubly charged ions in the desorption/ionization mechanism of FAB and MALDI is the result of deprotonation reactions to form singly charged ions of the type [M(2+) - H(+)](+) and of one-electron reductions to form radical cations [M(2+) + e(-)](+.). The dependence of this phenomenon and the formation of a number of additional ionic species on the different matrices and the FAB-matrix additive benzoquinone is examined. The significant analogous behavior of doubly charged porphyrins in FAB- and MALDI-MS leads to the conclusion that one-electron reductions are of distinct relevance in the desorption/ionization mechanism of MALDI.
Benzoquinones↗
Further isoflavonoid metabolites from Millettia griffoniana (Bail).
Three new isoflavonoids, griffonianone A (1), B (2) and C (4) were isolated from the root bark of Millettia griffoniana, along with the known maximaisoflavone G (5) and 7-hydroxy-6-methoxy-3',4'-methylenedioxyisoflavone (6). Their structures were assigned on the basis of spectroscopic data and chemical transformations.
Fabaceae↗
The structure of a pyoverdine produced by a Pseudomonas tolaasii-like isolate.
Cultures of Agaricus bisporus, the most extensively cultivated mushroom, can be infected severely by Pseudomonas tolaasii. This pathogen is characterized by the so-called white line reaction, a precipitate formed on agar plates between its colonies and those of P. reactans, both belonging to the collective species P. fluorescens. A recent study has shown that a group of P. tolaasii isolates can be subdivided into two groups or 'siderovars', based on the pyoverdines they produce (Munsch et al. 2000). One group of strains is characterized by the pyoverdine described by Demange et al. (1990). A representative of the second group (strain Ps3a) was found to produce the same pyoverdine as a strain which had been classified before as P. aureofaciens. However, based mainly on 16S rRNA gene sequence comparisons and REP-PCR generated fingerprints, the two strains are not identical. They are also distinguishable from the P. tolaasii type strain.
Agaricales↗
Influence of culture conditions on lipopeptide production by Bacillus subtilis.
Bacillus subtilis produces various families of lipopeptides with different homologous compounds. To produce "new molecules" with improved activities and to select strains that produced a reduced number of homologs or isomers, we studied the effects of different media on the nature of the synthesis of fatty acid chains for each lipopeptide family. This study focused on two B. subtilis strains cultivated in flasks. Optimized medium for lipopeptide production and Landy medium modified by replacing glutamic acid with other alpha-amino acids were used. We found that the intensity of production of homologous compounds depends on the strain and the culture medium. Analysis of these lipopeptides by high-performance liquid chromatography showed that the strain B. subtilis NT02 yielded various homologous compounds when cultivated in Landy medium (L-Glu), but primarily one homologous product in high relative amounts when cultivated in the optimized medium. Mass spectrometric analysis and determination of the amino acid composition of this molecule enabled us to identify it as Bacillomycine L c15.
Amino Acids↗
Siderophore-antibiotic conjugates used as trojan horses against Pseudomonas aeruginosa.
Pseudomonas aeruginosa is a dangerous opportunistic bacterium responsible for frequently lethal hospital (nosocomial) infections. It endangers especially severely injured patients suffering from large wounds or severe burns, as well as persons whose immune system is weakened. An extremely critical situation exists for patients suffering from mucoviscidosis (cystic fibrosis), when P. aeruginosa infects the bronchial tubes. P. aeruginosa is resistant against many disinfecting agents and, more important, an increasing number of strains especially from hospital isolates have become highly resistant against most antibiotics. The low permeability of the outer membrane and an active export mechanism for low molecular weight substances are the main reasons for the resistance. In addition, beta-lactamase activity affects treatment with beta-lactam antibiotics. An approach to overcome the problem of resistance lies in the synthesis of antibiotics conjugated with compounds active as siderophores. In this way the transport ways for iron complexes into the cell can be used ("Trojan Horse strategy"), and the presence of large substituents reduces the export and the beta-lactamase activity. The results obtained with natural (pyoverdins) and synthetic (mainly catecholate) siderophores will be reviewed.
Anti-Bacterial Agents↗
Siderophores of the human pathogenic fluorescent pseudomonads.
Bacteria need a sufficient supply of iron in ionic form for their metabolism. When living in an environment where this is not possible (as in the soil due to the presence of highly unsoluble ferric oxide hydrates, or in living organisms where iron is bound to peptidic chelators) Fe3+ complexing compounds, called siderophores, are produced. The siderophores of Pseudomonas aeruginosa, a dangerous opportunistic human pathogen, and of related potentially pathogenic species will be presented.
Fluorescence↗
Mass spectrometric analysis of hydroxyproline glycans.
Mass spectrometric techniques are presented which allow one to analyze the sugar part bound to hydroxyproline in hydroxyproline-rich glycoproteins. The hydroxyproline (Hyp) glycans obtained by alkaline hydrolysis give abundant [M + Na](+) ions by electrospray ionization which after collision-induced dissociation (CID) yield inter alia [Hyp - H + Na](+). In mixtures a parent ion scan of this species will indicate the various molecular species which can then be analyzed by MS(n) after CID in an ion trap, where successive losses of the sugar units are observed. Methylation techniques allow one to distinguish between linear and branched isomeric structures.
Animals↗
A pyoverdine from Pseudomonas putida CFML 90-51 with a Lys epsilon-amino link in the peptide chain.
From Pseudomonas putida CFML 90-51--a hospital isolate--a pyoverdine was obtained which is characterized by the unusual linkage by the epsilon--rather than the alpha-amino group of Lys in the peptide chain. The structure elucidation by spectroscopic methods and degradation reactions is reported.
Amino Acid Sequence↗
The structure of a pyoverdine from Pseudomonas sp. CFML 96.188 and its relation to other pyoverdines with a cyclic C-terminus.
From Pseudomonas sp. CFML 96.188 a pyoverdine was isolated and its primary structure was elucidated by spectroscopic methods and degradation reactions. This strain is of interest as it accepts the structurally different pyoverdines from several other Pseudomonas strains. They all have in common as a specific structural feature a C-terminal cyclic substructure, the importance of which for the recognition of a pyoverdine at the cell surface of a given strain will be discussed.
Amino Acid Sequence↗
Quinolobactin, a new siderophore of Pseudomonas fluorescens ATCC 17400, the production of which is repressed by the cognate pyoverdine.
Transposon mutant strain 3G6 of Pseudomonas fluorescens ATCC 17400 which was deficient in pyoverdine production, was found to produce another iron-chelating molecule; this molecule was identified as 8-hydroxy-4-methoxy-quinaldic acid (designated quinolobactin). The pyoverdine-deficient mutant produced a supplementary 75-kDa iron-repressed outer membrane protein (IROMP) in addition to the 85-kDa IROMP present in the wild type. The mutant was also characterized by substantially increased uptake of (59)Fe-quinolobactin. The 75-kDa IROMP was produced by the wild type after induction by quinolobactin-containing culture supernatants obtained from the pyoverdine-negative mutant or by purified quinolobactin. Conversely, adding purified wild-type pyoverdine to the growth medium resulted in suppression of the 75-kDa IROMP in the pyoverdine-deficient mutant; however, suppression was not observed when Pseudomonas aeruginosa PAO1 pyoverdine, a siderophore utilized by strain 3G6, was added to the culture. Therefore, we assume that the quinolobactin receptor is the 75-kDa IROMP and that the quinolobactin-mediated iron uptake system is repressed by the cognate pyoverdine.
Bacterial Outer Membrane Proteins↗
A fast screening method for the identification of siderophores from fluorescent Pseudomonas spp. by liquid chromatography/electrospray mass spectrometry.
A screening method was developed for the fast identification of known pyoverdin-type siderophores produced by fluorescent Pseudomonas spp. It is based on reversed-phase high-performance liquid chromatography interfaced with electrospray ionization mass spectrometry of the Sep-Pak RP-C18 culture supernatant extracts. The siderophores of five bacterial strains were characterized by their molecular masses obtained from their doubly protonated molecular ions [M + 2H]2+ and their UV/visible spectra recorded with a diode-array detector. Additional structural information was gained by skimmer collision-induced dissociation experiments. For all strains new minor siderophores were found. A table of fully or partially identified pyoverdins and related siderophores is provided which will be the basis for screening studies.
Chromatography, Liquid↗
Gas phase reaction rate measurements in Fourier transform mass spectrometry.
Determination of the concentration of neutral polycyclic aromatic hydrocarbon molecules in the mass spectrometer for reaction rate measurement is investigated. Copyright 1999 John Wiley & Sons, Ltd.
Journal Article↗
Synthesis and biological evaluation of a pyoverdin-beta-lactam conjugate: a new type of arginine-specific cross-linking in aqueous solution.
Arginine specific reagents such as phenylglyoxal and other alpha-dioxo compounds react with arginine side chains by forming adducts with a stoichiometry of 2:1 or a mixture of 2:1 and 1:1. These adducts are labile in neutral and slightly alkaline aqueous solution. We developed a new type of cross-linking reaction with aliphatic beta-dioxo compounds. They can be used for the well-defined, irreversible covalent attachment of molecules carrying a primary amino group to arginyl residues of water soluble peptides. The reaction proceeds under mild conditions in aqueous solution, essentially without the formation of side products. A pyoverdin-cephalexin conjugate was synthesized in order to promote its cellular uptake by Pseudomonas aeruginosa. Preliminary biological investigations of the conjugate indicated that it enters the bacterial cell via the pyoverdin-mediated iron uptake pathway.
Acylation↗