Enlightening mineral iron sensing in Pseudomonas fluorescens by surface active maghemite nanoparticles: Involvement of the OprF porin

Magro, Massimiliano, Fasolato, Luca, Bonaiuto, Emanuela , Andreani, Nadia, Baratella, Davide, Corraducci, Vittorino, Miotto, Giovanni, Cardazzo, Barbara and Vianello, Fabio (2016) Enlightening mineral iron sensing in Pseudomonas fluorescens by surface active maghemite nanoparticles: Involvement of the OprF porin. Biochimica et Biophysica Acta (BBA) - General Subjects, 1860 (10). pp. 2202-2210. ISSN 0304-4165

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Item Type:Article
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Background: Mineral iron(III) recognition by bacteria is considered a matter of debate. The peculiar surface chemistry of novel naked magnetic nanoparticles, called SAMNs (surface active maghemite nanoparticles) characterized by solvent exposed Fe3+ sites on their surface, was exploited for studying mineral iron sensing in Pseudomonas fluorescens.
Methods: SAMNs were applied for mimicking Fe3+ ions in solution, acting as magnetically drivable probes to evaluate putative Fe3+ recognition sites on the microorganism surface. Culture broths and nano-bio-conjugates were characterized by UV–Vis spectroscopy and mass spectrometry.
Results: The whole heritage of a membrane porin (OprF) of P. fluorescens Ps_22 cells was recognized and firmly bound by SAMNs. The binding of nanoparticles to OprF porin was correlated to a drastic inhibition of a siderophore (pyoverdine) biosynthesis and to the stimulation of the production and rate of formation of a secondary siderophore. The analysis of metabolic pathways, based on P. fluorescens Ps_22 genomic information, evidenced that this putative secondary siderophore does not belong to a selection of the most common siderophores.
Conclusions: In the scenario of an adhesion mechanism, it is plausible to consider OprF as the biological component deputed to the mineral iron sensing in P. fluorescens Ps_22, as well as one key of siderophore regulation.
General significance: The present work sheds light on mineral iron sensing in microorganisms. Peculiar colloidal naked iron oxide nanoparticles offer a useful approach for probing the adhesion of bacterial surface on mineral iron for the identification of the specific recognition site for this iron uptake regulation in microorganisms.

Keywords:Maghemite nanoparticles, Iron sensing, Oprf porin, Siderophores, Membrane proteins, Bacteria, JCNotOpen
Subjects:C Biological Sciences > C500 Microbiology
Divisions:College of Science > School of Life Sciences
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ID Code:27508
Deposited On:19 May 2017 09:51

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