ESTIMATION OF OXIDATIVE STRESS IN SACCHAROMYCES-CEREVISIAE WITH FLUORESCENT-PROBES

Oxidation of dichlorofluorescin and dihydrofluorescin and transport of their oxidation products were studied in Saccharomyces cerevisiae cel ls given diacetates of these compounds. It was found that addition of peroxidase significantly accelerates the formation of dichlorofluoresc ein and fluorescein, indicating that peroxidase activity may be a limi ting factor in studies of cellular oxidation using these probes, A sig nificant leakage of dichlorofluorescin and dihydrofluorescin, and of t heir oxidized forms from the yeast cells, was found, without any appar ent lag period, This phenomenon complicates interpretation of data obt ained with the fluorescent precursors used but, on the other hand, poi nts to the possibility of using measurements of dichlorofluorescein or fluorescein in the extracellular medium for studies of cellular oxida tion processes. (C) 1997 Elsevier Science Ltd. All rights reserved.