Enhancement of autofluorescence of the brown-rot fungus Piptoporus betulinus by metal ions.

The autofluorescence (primary fluorescence, AF) of agar cultures of the brown-rot fungus Piptoporus betulinus was investigated in Zeiss Jenalumar and Nikon Eclipse 8201 fluorescence microscopes at various excitations. The strongest AF of hyphae was found in minimal medium with glucose, where the hyphae exhibited green AF at violet (450 nm) excitation and red AF at green (570 nm) excitation. Addition of metals to cultivation media led to enhanced white-blue AF in the presence of Co (at 450 nm) and yellow to yellow-brown AF at 510 nm. When cultivated with Mn and Zn, enhanced AF of intracellular content was observed. Only a weak signal was found in the presence of Cu and Fe.