Quantification of Hydroxamate Siderophores in Soil Solutions of Podzolic Soil Profiles in Sweden

Abstract

Concentrations up to 2 and 12 nM of the hydroxamate siderophores ferrichrome and ferricrocin, respectively, were identified in soil solutions of podzolic forest soils at four sites in both northern and southern Sweden. No ferrichrysin was detected. As with the dissolved organic carbon and low molecular mass organic acids, the highest concentrations of the siderophores were found in the upper layers i.e. the mor layer, the eluvial and upper illuvial horizons. At the southern sites, the concentrations of ferrichrome and ferricrocin were both of similar magnitude and did not differ between the two sites. In contrast, soil solutions at the two northern sites contained more ferricrocin than ferrichrome; the ferricrocin concentrations were also higher at the northern sites than at the southern sites. Analyses were performed by high performance liquid chromatography with a porous graphitic carbon column on which ferrichrome, ferricrocin and ferrichrysin were separated. Detection by electrospray ionization mass spectrometry (ESI-MS) combined with on-line sample pre-concentration, by means of column-switching, enabled detection limits of 0.1-0.2 nM for ferrichrome, ferrichrysin and ferricrocin. The structural identities of the siderophores were further verified by MS/MS fragmentation. Fragmentation of ferrichrome, ferricrocin and ferrichrysin occurred mainly via peptide cleavage. The most intense fragments were typified by the loss of one of the three iron(III) chelating hydroxamate residues, i.e N(5)-acyl-N(5)-hydroxy ornithine.

Siderophore Production by Pseudomonas stutzeri under Aerobic and Anaerobic Conditions

“…In order to detect substances at low concentrations, column-switched capillary chromatography with MS detection was used. The detection limits of the combined LC-MS/MS system used in this study are in the range of 1 to 5 nM for hydroxamate siderophores of the ferrichrome and ferrioxamine families (9). In order to facilitate analysis of lower concentrations of ferrioxamines, natural water samples were preconcentrated by solid-phase extraction (SPE), resulting in minimum detectable concentrations in the range of 0.02 to 0.1 nM, depending on the initial sample volume.…”

Identification and characterization of Aeromonas hydrophila genes encoding the outer membrane receptor of ferrioxamine B and an AraC-type transcriptional regulator

“…In fact, different microbes that produce hydroxamate-type siderophores, including ferrioxamine species, are widely distributed in aquatic and terrestrial environments. [38][39][40][41][42] Future studies are required to characterize the inner membrane FOB transport system and elucidate the molecular mechanism by which desA transcription is induced by DesR in the presence of DFOB. Notes: ΔentAΔtonB1ΔtonB3 (circle), ΔentAΔtonB2ΔtonB3 (triangle), and ΔentAΔtonB1ΔtonB2 (square) were grown in the −Fe/+DFOB.…”

Identification of Genes, desR and desA, Required for Utilization of Desferrioxamine B as a Xenosiderophore in Vibrio furnissii

“…It has been reported that hydroxamate-type siderophores, including ferrioxamine species, and microbes that produce such siderophores are widely distributed in aquatic and terrestrial environments. [22][23][24][25] In addition, the expression of a specific IROMP stimulated by the presence of a xenosiderophore as an iron source would represent a common energy-saving strategy adopted by natural habitants of microbes. Future studies will be needed to elucidate the ABC transporter system genes for FOB in V. furnissii and molecular mechanisms The amounts of mRNA for desR, the desR-desA intergenic region, and desA were assessed with qPCR using the total RNA samples extracted from V. furnissii ATCC35016 and DdesR strains grown in the ϩFe and ϪFe media, and ϪFe medium with 20 mM DFOB.…”