Purification of Pyoverdines of Pseudomonas fluorescens 2-79 by Copper-Chelate Chromatography

Xiao, Rong; Kisaalita, William S.

doi:10.1128/aem.61.11.3769-3774.1995

Cited by 37 publications

(23 citation statements)

References 35 publications

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“…maxima of 400/460 at neutral pH, and double excitation peaks of 360 and 380 nm in acidic solution. And, these are similar to the spectra for other pyoverdins [18,19].…”

Section: Influence Of Immobilization Upon Pyoverdin Spectrasupporting

confidence: 81%

Leaching Behavior of a Fluorescent Pyoverdin Immobilized in Sol-Gel Glass

Yoder¹,

Kisaalita²

2008

TOBIOTJ

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The leaching behavior of fluorescent siderophore, pyoverdin (iron biosensor), immobilized in acid-catalyzed sol-gel glass is examined. By varying the R value (molar ratio of water:silicon), three different formulations of pyoverdindoped sol-gel glass pellets (R = 5.6, 8.2, 10.8) were made with tetramethyl orthosilicate (TMOS). At three different aging times (2, 4, and 6 weeks), 7-day leaching experiments were conducted on whole and ground pellets. Two different leaching solutions were used: 0.1 M acetate buffer, pH 5.0, and 1 M HCl. Pyoverdin immobilization resulted in conformation changes as suggested by the appearance of two emission peaks centered at 440 and 505 nm. As expected, pyoverdin leached more rapidly from the ground glass; 61 % of the pyoverdin leached from the ground glass within the first 20 minutes, while after 3 hours, only 54 % of the pyoverdin had leached from the whole pellets. As the sol-gel glass aged from 2 to 6 weeks, the initial fluorescence of the ground glass decreased by 34 – 46 % for the three sol-gel formulations, and the 7-day cumulative leachate decreased by 13 – 31 %. However, sol-gel with the lowest R value (5.6) retained pyoverdin better that sol-gels at higher R values. The release of pyoverdin was also characterized by the diffusional exponent (n), which ranged from 0.527 to 0.802 for the ground glass, and from 0.276 to 0.415 for the whole pellets, confirming that whole pellets retained pyoverdin better than ground glass. Taken together, the results suggest for a given sensor configuration, retention of pyoverdin can be optimized with respect to pellet size, R value and aging time.

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“…maxima of 400/460 at neutral pH, and double excitation peaks of 360 and 380 nm in acidic solution. And, these are similar to the spectra for other pyoverdins [18,19].…”

Section: Influence Of Immobilization Upon Pyoverdin Spectrasupporting

confidence: 81%

Leaching Behavior of a Fluorescent Pyoverdin Immobilized in Sol-Gel Glass

Yoder¹,

Kisaalita²

2008

TOBIOTJ

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“…2C). This was reflected in the UV spectrum of the culture supernatants as an appearance of a typical peak with an absorption maximum around 400 nm (Xiao and Kisaalita, 1995) (Fig. S4A).…”

Section: Strain Svbp6 Produces a Soluble Compound Compatible With 7htmentioning

confidence: 97%

7‐hydroxytropolone is the main metabolite responsible for the fungal antagonism of Pseudomonas donghuensis strain SVBP6

Muzio

Agaras

Masi

et al. 2020

Environmental Microbiology

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Summary Pseudomonas donghuensis strain SVBP6, an isolate from an agricultural plot in Argentina, displays a broad‐spectrum and diffusible antifungal activity, which requires a functional gacS gene but could not be ascribed yet to known secondary metabolites typical of Pseudomonas biocontrol species. Here, we report that Tn5 mutagenesis allowed the identification of a gene cluster involved in both the fungal antagonism and the production of a soluble tropolonoid compound. The ethyl acetate extract from culture supernatant showed a dose‐dependent inhibitory effect against the phytopathogenic fungus Macrophomina phaseolina. The main compound present in the organic extract was identified by spectroscopic and X‐ray analyses as 7‐hydroxytropolone (7HT). Its structure and tautomerism was confirmed by preparing the two key derivatives 2,3‐dimethoxy‐ and 2,7‐dimethoxy‐tropone. 7HT, but not 2,3‐ or 2,7‐dimethoxy‐tropone, mimicked the fungal inhibitory activity of the ethyl acetate extract from culture supernatant. The activity of 7HT, as well as its production, was barely affected by the presence of up to 50 μM added iron (Fe+2). To summarize, P. donghuensis SVBP6 produces 7HT under the positive control of the Gac‐Rsm cascade and is the main active metabolite responsible for the broad‐spectrum inhibition of different phytopathogenic fungi.

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“…Further, it is well established fact that Pseudomonas spp. cultures contain multiple siderophores (Cornelis and Matthijs, 2002;Kisaalita, 1995 and. However, purification of individual siderophores only add to the comprehensive sophistication undesired for several simplified applications.…”

Section: Introductionmentioning

confidence: 99%

Spectrophotometric ferric ion biosensor from Pseudomonas fluorescens culture

Gupta

Saharan

Kumar

et al. 2007

Biotech & Bioengineering

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Pseudomonas fluorescens cultures produce fluorescent siderophores. By utilizing optimal conditions for maximizing siderophore production in shake flask cultures of P. fluorescens, we report successful characterization of the culture broth supernatant as a robust ferric ions biosensor. For characterizing the ferric ions biosensor, we tested the effects of pH, buffers, different ferric salts and possible interference by ferrous ions under different solution conditions. We find that the biosensor is very specific to ferric ions only with sensitivity to concentrations as low as 10 microM. Further, the response time of the biosensor is the shortest (approximately 5 min or smaller) for citrate as the accompanying anion with ferric ions. While the response time is longer than that expected of normal biosensors, it is well compensated by the simplicity and economics of the biosensor production. Extremely low standard deviations in several experimental repeats also highlight the robustness of the ferric ions biosensor. Most importantly, the biosensor is extremely easy to use due to its straightforward spectrophotometric applications. We also show the utility of the biosensor with the high resolution technique of fluorescence microscopy. Finally, we report a novel mechanistic finding that siderophores present in the culture broth supernatants have two distinct optically active sites on them, which can be monitored independently in presence or absence of ferric ions.

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Purification of Pyoverdines of Pseudomonas fluorescens 2-79 by Copper-Chelate Chromatography

Cited by 37 publications

References 35 publications

Leaching Behavior of a Fluorescent Pyoverdin Immobilized in Sol-Gel Glass

Leaching Behavior of a Fluorescent Pyoverdin Immobilized in Sol-Gel Glass

7‐hydroxytropolone is the main metabolite responsible for the fungal antagonism of Pseudomonas donghuensis strain SVBP6

Spectrophotometric ferric ion biosensor from Pseudomonas fluorescens culture

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