EPR examination of Zn2+ and Cu2+ binding by pigmented soil fungi Cladosporium cladosporioides.
The purpose of this study was to examine the usefulness of electron paramagnetic resonance spectroscopy (EPR) to estimate zinc and copper ions biosorption from the environment by pigmented soil fungi Cladosporium cladosporioides. The existence of a low amount of pheomelanin, besides eumelanin, in C. cladosporioides samples was proved by the analysis of shape of their EPR spectra. Concentration of o-semiquinone free radicals in crude mycelium was 2.4x10(17) spin/g. Changes in free radicals system of C. cladosporioides cultured in the presence of Zn2+ and Cu2+ were analysed. Both magnetic and chemical interactions of zinc and copper ions with free radicals in C. cladosporioides melanin were found. Magnetically interacting diamagnetic Zn2+ ions increased the concentration of o-semiquinone free radicals in melanin existing in C. cladosporioides mycelium, whereas paramagnetic Cu2+ ions decreased this concentration. Chemical interactions of Zn2+ and Cu2+ ions decreased the free radical concentrations in C. cladosporioides melanin. Homogeneously distributed free radicals in C. cladosporioides melanin rise its activity in biosorption processes.
Department of Pharmaceutical Chemistry, School of Pharmacy, Medical University of Silesia, Jagielloñska 4, 41-200 Sosnowiec, Poland. ebuszman@slam.katowice.pl
Ewa
E
Buszman
Barbara
B
Pilawa
Magdalena
M
Zdybel
Sławomir
S
Wilczyński
Anna
A
Gondzik
Teresa
T
Witoszyńska
Tadeusz
T
Wilczok
D000327:Adsorption; D016227:Benzoquinones / Q000032:analysis; D002413:Cations, Divalent; D002963:Cladosporium / Q000378:metabolism* / Q000528:radiation effects*; D003300:Copper / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D008543:Melanins / Q000378:metabolism* / Q000528:radiation effects*; D008872:Microwaves; D010860:Pigments, Biological; D012987:Soil; D015032:Zinc / Q000378:metabolism*
D016227:Benzoquinones; D002413:Cations, Divalent; D008543:Melanins; D010860:Pigments, Biological; D012987:Soil; C025232:semiquinone radicals; D003300:Copper; D015032:Zinc