Hc. Yang et al., RAPID VIABILITY ASSESSMENT OF SPORES OF SEVERAL FUNGI BY AN IONIC INTENSIFIED FLUORESCEIN DIACETATE METHOD, Current microbiology, 30(3), 1995, pp. 173-176
Fluorescein diacetate (FDA) was applied to the viability assessment of
spores of Aspergillus niger, Rhizopus stolonifer, Fusarium oxysporum,
and Penicillium citrinum. The fluorescence of individual cells was qu
antitated with a charge coupled device (CCD) detector. When staining w
as carried out in a phosphate buffer solution (10 mM, pH 7.0), weak or
no fluorescence was emitted from viable spores of A. niger and R. sto
lonifer, which made it difficult to distinguish between viable (nontre
ated) and nonviable (heat treated at 90 degrees C for 30 min) spores.
The addition of NaCl, KCl, or MgCl2 to the staining solution caused an
increase in the fluorescence intensity of A. niger viable spores, fro
m which nonviable spores could be distinguished. The same effect of Na
Cl was observed in staining the spores of other species.