scholarly journals Pseudomonas fluorescens CHA0 Produces Enantio-pyochelin, the Optical Antipode of the Pseudomonas aeruginosa Siderophore Pyochelin

2007 ◽  
Vol 282 (49) ◽  
pp. 35546-35553 ◽  
Author(s):  
Zeb A. Youard ◽  
Gaëtan L. A. Mislin ◽  
Paul A. Majcherczyk ◽  
Isabelle J. Schalk ◽  
Cornelia Reimmann
Keyword(s):  
Gene Expression ◽  
Mass Spectrometry ◽  
Pseudomonas Aeruginosa ◽  
Pseudomonas Fluorescens ◽  
Biosynthetic Pathway ◽  
Cysteine Residue ◽  
Iron Limitation ◽  
Chiral Hplc ◽  
Optical Antipode ◽  
Layer Chromatography

The siderophore pyochelin is made by a thiotemplate mechanism from salicylate and two molecules of cysteine. In Pseudomonas aeruginosa, the first cysteine residue is converted to its D-isoform during thiazoline ring formation whereas the second cysteine remains in its L-configuration, thus determining the stereochemistry of the two interconvertible pyochelin diastereoisomers as 4 ′R, 2 ″R, 4 ″R (pyochelin I) and 4 ′R, 2 ″S, 4 ″R (pyochelin II). Pseudomonas fluorescens CHA0 was found to make a different stereoisomeric mixture, which promoted growth under iron limitation in strain CHA0 and induced the expression of its biosynthetic genes, but was not recognized as a siderophore and signaling molecule by P. aeruginosa. Reciprocally, pyochelin promoted growth and induced pyochelin gene expression in P. aeruginosa, but was not functional in P. fluorescens. The structure of the CHA0 siderophore was determined by mass spectrometry, thin-layer chromatography, NMR, polarimetry, and chiral HPLC as enantio-pyochelin, the optical antipode of the P. aeruginosa siderophore pyochelin. Enantio-pyochelin was chemically synthesized and confirmed to be active in CHA0. Its potential biosynthetic pathway in CHA0 is discussed.

scholarly journals Different Responses of Pyoverdine Genes to Autoinduction in Pseudomonas aeruginosa and the Group Pseudomonas fluorescens-Pseudomonas putida

2002 ◽  
Vol 68 (8) ◽  
pp. 4122-4126 ◽  
Author(s):  
Cecilia Ambrosi ◽  
Livia Leoni ◽  
Paolo Visca
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pseudomonas Putida ◽  
Pseudomonas Fluorescens ◽  
Biosynthetic Pathway ◽  
Control Circuit ◽  
Positive Regulation

ABSTRACT We investigated the regulation of the psbA and pvdA pyoverdine biosynthesis genes, which encode the l-ornithine N 5-oxygenase homologues in Pseudomonas strain B10 and Pseudomonas aeruginosa PAO1, respectively. We demonstrate that pyoverdineB10, as the end product of its biosynthetic pathway, is a key participant of the control circuit regulating its own production in Pseudomonas strain B10. In P. aeruginosa PAO1, however, pyoverdinePAO1 has no apparent role in the positive regulation of the pvdA gene.

scholarly journals SpoT-Triggered Stringent Response Controls usp Gene Expression in Pseudomonas aeruginosa

2008 ◽  
Vol 190 (21) ◽  
pp. 7189-7199 ◽  
Author(s):  
Nelli Boes ◽  
Kerstin Schreiber ◽  
Max Schobert
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Stress Proteins ◽  
Stringent Response ◽  
Triple Mutant ◽  
Pyruvate Fermentation ◽  
Anaerobic Energy ◽  
In The Wild ◽  
Layer Chromatography

ABSTRACT The universal stress proteins (Usps) UspK (PA3309) and UspN (PA4352) of Pseudomonas aeruginosa are essential for surviving specific anaerobic energy stress conditions such as pyruvate fermentation and anaerobic stationary phase. Expression of the respective genes is under the control of the oxygen-sensing regulator Anr. In this study we investigated the regulation of uspN and three additional P. aeruginosa usp genes: uspL (PA1789), uspM (PA4328), and uspO (PA5027). Anr induces expression of these genes in response to anaerobic conditions. Using promoter-lacZ fusions, we showed that P uspL -lacZ, P uspM -lacZ, and P uspO -lacZ were also induced in stationary phase as described for P uspN -lacZ. However, stationary phase gene expression was abolished in the P. aeruginosa triple mutant Δanr ΔrelA ΔspoT. The relA and spoT genes encode the regulatory components of the stringent response. We determined pppGpp and ppGpp levels using a thin-layer chromatography approach and detected the accumulation of ppGpp in the wild type and the ΔrelA mutant in stationary phase, indicating a SpoT-derived control of ppGpp accumulation. Additional investigation of stationary phase in LB medium revealed that alkaline pH values are involved in the regulatory process of ppGpp accumulation.

scholarly journals Pseudomonas aeruginosa 1244 Pilin Glycosylation: Glycan Substrate Recognition

2006 ◽  
Vol 188 (12) ◽  
pp. 4244-4252 ◽  
Author(s):  
Joseph Horzempa ◽  
Charles R. Dean ◽  
Joanna B. Goldberg ◽  
Peter Castric
Keyword(s):  
Mass Spectrometry ◽  
Pseudomonas Aeruginosa ◽  
Structural Analysis ◽  
Western Blotting ◽  
Biosynthetic Pathway ◽  
Substrate Recognition ◽  
O Antigen ◽  
Recognition Elements ◽  
Glycosylation Reaction

ABSTRACT The pilin of Pseudomonas aeruginosa 1244 is glycosylated with an oligosaccharide that is structurally identical to the O-antigen repeating unit of this organism. Concordantly, the metabolic source of the pilin glycan is the O-antigen biosynthetic pathway. The present study was conducted to investigate glycan substrate recognition in the 1244 pilin glycosylation reaction. Comparative structural analysis of O subunits that had been previously shown to be compatible with the 1244 glycosylation machinery revealed similarities among sugars at the presumed reducing termini of these oligosaccharides. We therefore hypothesized that the glycosylation substrate was within the sugar at the reducing end of the glycan precursor. Since much is known of PA103 O-antigen genetics and because the sugars at the reducing termini of the O7 (strain 1244) and O11 (strain PA103) are identical (β-N-acetyl fucosamine), we utilized PA103 and strains that express lipopolysaccharide (LPS) with a truncated O-antigen subunit to test our hypothesis. LPS from a strain mutated in the wbjE gene produced an incomplete O subunit, consisting only of the monosaccharide at the reducing end (β-d-N-acetyl fucosamine), indicating that this moiety contained substrate recognition elements for WaaL. Expression of pilAO 1244 in PA103 wbjE::aacC1, followed by Western blotting of extracts of these cells, indicated that pilin produced has been modified by the addition of material consistent with a single N-acetyl fucosamine. This was confirmed by analyzing endopeptidase-treated pilin by mass spectrometry. These data suggest that the pilin glycosylation substrate recognition features lie within the reducing-end moiety of the O repeat and that structures of the remaining sugars are irrelevant.

scholarly journals Stereospecific recognition of pyochelin and enantio-pyochelin by the PchR proteins in fluorescent pseudomonads

Microbiology ◽  
2010 ◽  
Vol 156 (6) ◽  
pp. 1772-1782 ◽  
Author(s):  
Zeb A. Youard ◽  
Cornelia Reimmann
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Transcriptional Regulation ◽  
Pseudomonas Fluorescens ◽  
Outer Membrane ◽  
Growth Promotion ◽  
Membrane Receptors ◽  
Iron Limitation ◽  
Fluorescent Pseudomonads ◽  
Terminal Domain ◽  
Native Ligand

The siderophore pyochelin of Pseudomonas aeruginosa promotes growth under iron limitation and induces the expression of its biosynthesis genes via the transcriptional AraC/XylS-type regulator PchR. Pseudomonas fluorescens strain CHA0 makes the optical antipode of pyochelin termed enantio-pyochelin, which also promotes growth and induces the expression of its biosynthesis genes when iron is scarce. Growth promotion and signalling by pyochelin and enantio-pyochelin are highly stereospecific and are known to involve the pyochelin and enantio-pyochelin outer-membrane receptors FptA and FetA, respectively. Here we show that stereospecificity in signalling is also based on the stereospecificity of the homologous PchR proteins of P. aeruginosa and P. fluorescens towards their respective siderophore effectors. We found that PchR functioned in the heterologous species only if supplied with its native ligand and that the FptA and FetA receptors enhanced the efficiency of signalling. By constructing and expressing hybrid and truncated PchR regulators we showed that the weakly conserved N-terminal domain of PchR is responsible for siderophore specificity. Thus, both uptake and transcriptional regulation confer stereospecificity to pyochelin and enantio-pyochelin biosynthesis.

ANTI-CANCER COMPOUNDS ISOLATED FROM SOFT CORAL SINULARIA CRUCIATA - ALCYONIIDAE

2012 ◽  
pp. 84-89
Author(s):  
Quoc Hung Vo ◽  
Nguyen Phuong Nhi Doan ◽  
Dinh Quynh Phu Nguyen ◽  
Thi Dieu Tram Ho ◽  
Thi Hoai Nguyen
Keyword(s):  
Mass Spectrometry ◽  
Soft Coral ◽  
Normal Phase ◽  
Ionization Mass ◽  
Medical Field ◽  
Bioactive Substances ◽  
Anti Cancer ◽  
The World ◽  
Pure Compounds ◽  
Layer Chromatography

Objectives: Nowadays, bioactive substances isolated from marine organisms which are abundant and varied in Vietnamese sea attracted more and more the attention of scientists in the world and Vietnam as well. We have studied on soft coral Sinularia cruciata – Alcyoniidae, which has never been studied in Vietnam before, to find substances which are useful in medical field, especially in anti-cancer therapy. Materials and method: Specimens of soft coral Sinularia cruciata were collected from Con Co, Quang Tri province in May 2011. Pure compounds were isolated by using Thin Layer Chromatography; Column Chromatography normal phase and inverse phase; Shephadex LH 20. Structures of them were determined by spectral data of Nuclear Magnetic Resonance (NMR), Electrospray Ionization Mass Spectrometry (ESI-MS). Results & Conclusion: Structures of 4 compounds were identified: (1) 5.8-epidioxycholest-6-en-3-ol (2) Cholesterol (3) 1-O-hexadecyl-glycerol (Chimyl alcohol) (4) Glycerol 1-O-octadecyl ether (Batyl alcohol). The substance (1) was demonstrated to have strong anti-cancer effects in previous study. Key words Sinularia cruciata, Alcyoniidae, 5,8-epidioxycholest-6-en-3-ol, soft coral, cancer.

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