Figure 4.

Estimates of total cellular diene conjugates (DCs) and reactive oxygen species (ROS) level in the glycerol—(A) and glucose—(B) assimilating E. magnusii yeasts, raised at different growth stages. The dynamics of intracellular ROS production was monitored using a spectroscopic fluorescence probe of dihydro-2′,7′-dichlorofluorescein diacetate ester H₂DCF-DA. Total cellular DCs were extracted by the mixture of heptane and isopropyl and centrifuged at 4000× g for 10 min. The supernatant was mixed with some water, the heptane phase was dissolved in ethanol. The spectra of ultraviolet absorption scans between 220 and 300 nm were measured using the Beckman DU-8 spectrophotometer with the appearance of the maximum in the area of 232–234 nm and a shoulder in the area of 260–280 nm. A molar extinction coefficient of 2.2 × 105 × M⁻¹ × s⁻¹ cm^−l was used for the calculation of the DCs. The incubation medium for the experiments contained 50 mM KPi, pH 5.5; and 1% glucose. Values are mean ± S.E.M from 5–6 independent experiments. The intensity of ROS production in the version of «positive control» made up 234195.83 fluorescence intensity, units. a, b, c—0.05 > p > 0.005.