Fig. 3

Cytosolic Ca²⁺ levels in T. reesei QM6a and Δacy1 strains under different conditions. a The analysis of cytosolic Ca²⁺ levels using the Ca²⁺ fluorescent probe Fluo-4 AM. The QM6a and Δacy1 strains were cultured in MM with 2% glucose as the carbon source, then inoculated to fresh MM supplemented with 10 mM Mn²⁺, 1% DMF, 0.02 mΜ Forskolin, or 5 mM dbcAMP with 1% Avicel as the carbon source. Cultures with no addition was used as the controls. Fluo-4 AM (50 μM) was used for detection. The intensity was monitored using automatic inverted fluorescence microscopy. Green fluorescence intensity represents the free cytosolic Ca²⁺ levels. DIC, differential interference contrast. The control images of QM6a were also used in Fig. 5a. b Comparative fluorescence ratio analysis of different supplementation on cytosolic Ca²⁺ levels in T. reesei QM6a and Δacy1 strains. The y-axis represents the Ca²⁺ fluorescence ratio measured by CLSM, and the x-axis represents the different strains tested. Values are the means ± SEM of the results from three independent experiments. Asterisks indicate significant differences from the control (*p < 0.05, Student’s t test)