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Anal Bioanal Chem. 2015 Sep;407(24):7487-96. doi: 10.1007/s00216-015-8916-7. Epub 2015 Aug 8.

X-ray absorption near-edge structure micro-spectroscopy study of vanadium speciation in Phycomyces blakesleeanus mycelium.

Author information

1
Institute for Multidisciplinary Research, Department of Life Sciences, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia. mzizic@imsi.rs.
2
CELLS - ALBA, Carretera BP 1413, de Cerdanyola del Vallès a Sant Cugat del Vallès, km. 3,3, 08290, Cerdanyola del Vallès, Barcelona, Spain.
3
Swiss Light Source, Paul Scherrer Institute, 5232, Villigen-PSI, Switzerland.
4
Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000, Belgrade, Serbia.
5
Institute for Multidisciplinary Research, Department of Life Sciences, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia.
6
Institute of General and Physical Chemistry, NMR Laboratory, Studentski trg 12-16, 11000, Belgrade, Serbia.

Abstract

Vanadium speciation in the fungus Phycomyces blakesleeanus was examined by X-ray absorption near-edge structure (XANES) spectroscopy, enabling assessment of oxidation states and related molecular symmetries of this transition element in the fungus. The exposure of P. blakesleeanus to two physiologically important vanadium species (V(5+) and V(4+)) resulted in the accumulation of this metal in central compartments of 24 h old mycelia, most probably in vacuoles. Tetrahedral V(5+), octahedral V(4+), and proposed intracellular complexes of V(5+) were detected simultaneously after addition of a physiologically relevant concentration of V(5+) to the mycelium. A substantial fraction of the externally added V(4+) remained mostly in its original form. However, observable variations in the pre-edge-peak intensities in the XANES spectra indicated intracellular complexation and corresponding changes in the molecular coordination symmetry. Vanadate complexation was confirmed by (51)V NMR and Raman spectroscopy, and potential binding compounds including cell-wall constituents (chitosan and/or chitin), (poly)phosphates, DNA, and proteins are proposed. The evidenced vanadate complexation and reduction could also explain the resistance of P. blakesleeanus to high extracellular concentrations of vanadium.

KEYWORDS:

Phycomyces blakesleeanus; Raman spectroscopy; Vanadium; X-ray absorption near-edge structure

PMID:
26253227
DOI:
10.1007/s00216-015-8916-7
[Indexed for MEDLINE]

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