Virus and siderophore-mediated transfer of available Fe between heterotrophic bacteria: characterization using an Fe-specific bioreporter

Abstract

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 41:233-245 (2005) - doi:10.3354/ame041233 Virus and siderophore-mediated transfer of available Fe between heterotrophic bacteria: characterization using an Fe-specific bioreporter Cécile E. Mioni1,2,*, Leo Poorvin1,*, Steven W. Wilhelm2,** 1The Department of Microbiology, and 2The Center for Environmental Biotechnology, The University of Tennessee, 1414 West Cumberland, Knoxville, Tennessee 37996 0845, USA *These authors contributed equally to this study **Corresponding author. Email: [e-mail] ABSTRACT: Although marine chemists can accurately quantify both the concentration of dissolved iron (Fe) and the high-affinity organic ligands which complex Fe in surface waters, tools to characterize the relative bioavailability of such organically bound Fe complexes remain unavailable. In this study, we compared the bioavailability of Fe released from the lysis of the heterotrophic bacterium Vibrio natriegens PWH3a to that of Fe complexed to synthetic chelators (EDTA) and siderophores (including the trihydroxamate desferrioxamine B [DFB] and 2 catecholates isolated from Fe-limited heterotrophic bacterial cultures) using a heterotrophic bioluminescent reporter of Fe availability (Pseudomonas putida FeLux). Using the bioluminescent response of P. putida FeLux, we were able to rank the Fe sources tested here in a decreasing order of bioavailability: lysates > Fe-homologous catecholate (from a P. putida FeLux culture) ~ Fe-exogenous catecholate (from V. natriegens culture) > inorganic Fe (FeCl3, 15 nM) ~ Fe(III)' from EDTA-buffered treatment (pFe 18.12) > Fe:DFB, where pFe is –log [Fe3+]. Combined with estimates of Fe assimilation of 55Fe-labeled lysates, our data further demonstrate that organic Fe complexes released during virus-mediated cell lysis are ca. 1000 times more bioavailable and efficiently assimilated by bacterial cells than Fe(III)'. Our results validate the utilization of P. putida FeLux as a bioreporter of Fe-bioavailability and also support the assumption that virus activity plays a crucial role in the regeneration of biologically available Fe complexes in surface seawater. KEY WORDS: Iron availability · Bioreporter · Heterotrophic bacteria · Siderophore · Virus lysates Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 41, No. 3. Online publication date: December 23, 2005 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2005 Inter-Research.