Metabolic responses of cultured cells to oxygenated perfluorocarbon

Protoplast-derived cells of albino Petunia hybrida cv. Comanche were used as a model, nonphotosynthetic, eukaryotic plant system to study changes in (1) the rate of oxygen consumption as measured by a Clark-type oxygen microelectrode, (2) mitochondrial membrane potential (MMP) as assessed by Rhodamine 123 fluorescence, and (3) intracellular activities of superoxide dismutases (SOD, EC 1.15.1.1) and catalases (CAT, EC 1.11.1.6), following culture for up to 14 d in aqueous nutrient medium overlaying oxygen-gassed perfluorodecalin (Flutec PP5; F2 Chemicals, Preston, UK). The mean (+/- s.e.m., n = 7) rate of oxygen consumption of Petunia cells after 24 h of culture in the presence of oxygenated PFC was 14.3 +/- 1.6 mol O2 ml(-1) min(-1), compared to 9.7 +/- 0.8 micromol O2 ml(-1) min(-1) for untreated (control) cells (P < 0.05). Similarly, the culture of cells with oxygenated PFC for 24 h resulted in a significant (P < 0.05) increase of over 50% in the mean MMP, compared to the control. Culture of protoplasts with oxygenated PFC also produced significant (P < 0.05) increases in both mean SOD and CAT activities after 3-7 d of culture, the former comparable to that reported previously for protoplasts of Salpiglossis sinuata cultured with oxygenated PFC.