Secondary metabolites from fluorescent pseudomonads

Budzikiewicz, H.

doi:10.1016/0378-1097(93)90597-u

Cited by 86 publications

(146 citation statements)

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“…Many HAQs have been previously identified as P. aeruginosa secondary metabolites (36,43). We confirm that a number of these compounds have Gram-positive antimicrobial activity and attribute some of this activity to HQNO, the most abundant HAQ.…”

Section: Discussionmentioning

confidence: 99%

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Analysis of Pseudomonas aeruginosa 4-hydroxy-2-alkylquinolines (HAQs) reveals a role for 4-hydroxy-2-heptylquinoline in cell-to-cell communication

Déziel

Lépine

Milot

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

583

743

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Bacterial communities use ''quorum sensing'' (QS) to coordinate their population behavior through the action of extracellular signal molecules, such as the N-acyl-L-homoserine lactones (AHLs). The versatile and ubiquitous opportunistic pathogen Pseudomonas aeruginosa is a well-studied model for AHL-mediated QS. This species also produces an intercellular signal distinct from AHLs, 3,4-dihydroxy-2-heptylquinoline (PQS), which belongs to a family of poorly characterized 4-hydroxy-2-alkylquinolines (HAQs) previously identified for their antimicrobial activity. Here we use liquid chromatography (LC)͞MS, genetics, and whole-genome expression to investigate the structure, biosynthesis, regulation, and activity of HAQs. We show that the pqsA-E operon encodes enzymes that catalyze the biosynthesis of five distinct classes of HAQs, and establish the sequence of synthesis of these compounds, which include potent cytochrome inhibitors and antibiotics active against human commensal and pathogenic bacteria. We find that anthranilic acid, the product of the PhnAB synthase, is the primary precursor of HAQs and that the HAQ congener 4-hydroxy-2-heptylquinoline (HHQ) is the direct precursor of the PQS signaling molecule. Significantly, whereas phnAB and pqsA-E are positively regulated by the virulence-associated transcription factor MvfR, which is also required for the expression of several QSregulated genes, the conversion of HHQ to PQS is instead controlled by LasR. Finally, our results reveal that HHQ is itself both released from, and taken up by, bacterial cells where it is converted into PQS, suggesting that it functions as a messenger molecule in a cell-to-cell communication pathway. HAQ signaling represents a potential target for the pharmacological intervention of P. aeruginosa-mediated infections.

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Section: Discussionmentioning

confidence: 99%

“…Fluorescent pseudomonads, and perhaps just P. aeruginosa, are the only microorganisms identified to produce HAQs (9,36). Although their biological functions are unknown, many HAQs were initially isolated as antibiotics (10,11).…”

Section: Haq Activity: Mvfr Regulates Hqno Antimicrobial Activity Agamentioning

confidence: 99%

Analysis of Pseudomonas aeruginosa 4-hydroxy-2-alkylquinolines (HAQs) reveals a role for 4-hydroxy-2-heptylquinoline in cell-to-cell communication

Déziel

Lépine

Milot

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

583

743

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“…The pyoverdin fluorescence can be easily detected under excitation by visible light at wavelengths !400 nm, whereas the pyochelin fluorescence could be identified only under UV-light at the wavelengths 350 nm [14]. Due to the strong fluorescence and a remarkable affinity for iron (as well as for other metal cations), pyoverdin is used as an optical biosensor for the determination of the trace amount of Fe III in water and soil [15,16]. It has been established that PaA is secreted in the outer membrane of P. aeruginosa and after complexing iron is transported into the bacterial cell via the receptor protein of the outer membrane FpvA, the natural form of which is the FpvA-PaA complex [17,18].…”

Section: Introductionmentioning

confidence: 99%

Interaction of the photobactericides methylene blue and toluidine blue with a fluorophore in Pseudomonas aeruginosa cells

Усачева¹,

Teichert²,

Usachev

et al. 2008

Lasers Surg Med

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Background and Objectives: The difference in photobactericidal efficacy between methylene blue (MB) and toluidine blue (TB) may be explained by their involvement with proteins, lipopolysaccharides (LPS), and siderophores and siderophore-receptor protein complexes on the bacterial outer membrane. This study aims to determine if this is the case by using the fluorescence given off by a pseudomonal siderophore named pyoverdin. Study Design/Materials and Methods: Confocal laser scanning microscopy was used to observe the fluorescence of Pseudomonas aeruginosa cells excited at 488 nm in the presence of increasing dye concentrations. Results: Cellular fluorescence at 522 nm progressively decreased with increasing dye concentrations. The SternVolmer constants for cellular fluorescence quenching with the dyes were compared to the association constants for dyes complexed with LPS. The quenching of cellular fluorescence was associated with the formation of a ground-state complex between the dyes and pyoverdin-FpvA protein system. MB readily complexed with this system, whereas TB complexed more strongly with LPS. Conclusion: The different affinities of the dyes for both pyoverdin-protein and LPS will affect the contributions of the dyes' interactions with these biopolymers to the overall bacterial photodamage.

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“…Siderophore assays were performed on supernatants diluted with 0.1 M Na-phosphate buffer pH 7.0 (100 µL sample: 900 µL buffer) by scanning with a Perkin-Elmer Lambda Bio (A 600 to A 190 ). The spectrum of salicylic acid (Merck) was also measured to compare its data with G7 medium measurements, since this organic acid is part of some small secreted iron-scavenger molecules (Cox et al, 1981;Ankenbauer and Cox, 1988;Budzikiewicz, 1993;Cornelis and Matthijs, 2002;Crosa and Wlash, 2002). Stock solution of 1 g salicylic acid /100 mL CHCl 3 was prepared and further dilutions were made to give a final concentration of 50 µg salicylic acid mL -1 .…”

Section: Measurement Of Growth and Pigment Formationmentioning

confidence: 99%

“…Pyoverdine is a more complex molecule in that it contains a quinoline chromophore, a peptide chain, and a dicarboxylic acid (Budzikiewicz, 1993). Meyer et al (1992) showed that the spectrum of salicylic acid from P. fluorescens and from a commercial source had the same graphic behaviour but differed totally from the pyochelin spectrum formed by P. aeruginosa.…”

Section: Spectrogram Of Prepared Media (Fye) Commercial Yeast Extracmentioning

confidence: 99%

Production of yellow-green fluorescent pigment by Pseudomonas fluorescens

Silva

Almeida

2006

Braz. arch. biol. technol.

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Secondary metabolites from fluorescent pseudomonads

Cited by 86 publications

References 0 publications

Analysis of Pseudomonas aeruginosa 4-hydroxy-2-alkylquinolines (HAQs) reveals a role for 4-hydroxy-2-heptylquinoline in cell-to-cell communication

Analysis of Pseudomonas aeruginosa 4-hydroxy-2-alkylquinolines (HAQs) reveals a role for 4-hydroxy-2-heptylquinoline in cell-to-cell communication

Interaction of the photobactericides methylene blue and toluidine blue with a fluorophore in Pseudomonas aeruginosa cells

Production of yellow-green fluorescent pigment by Pseudomonas fluorescens

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