Fig. 3

External pH, intracellular pH, and mitochondrial activity of T. reesei strains. External pH was measured in Δ76238 and the parental strain T. reesei RUT-C30 containing glucose (a), and lactose (b) as the carbon source. External pH was measured with a pH electrode. c Intracellular pH of Δ76238 and parental strain T. reesei RUT-C30 was characterized at 96 h, with glucose and lactose as the sole carbon source. Mycelia of T. reesei strains were labeled with 5 μM fluorescent pH probe BCECF-AM for 30 min. d Mitochondrial activity of Δ76238 and parental strain T. reesei RUT-C30 was measured using glucose or lactose as the carbon source at 96 h. Mycelia of T. reesei strains were stained with 100 nM MitoTracker^® Red CMXRos for 30 min. Values are the mean ± SD of results from three independent experiments. Asterisks indicate significant differences (**p < 0.01, ***p < 0.001, Student’s t test)