Fig. 9

Analysis of pH dependent promoter response of selected genes by translational reporters. (A) The indicated GFP-derived reporters were introduced in K. phaffii X-33 cells and cultures were shifted to the different pHs by addition of KOH. Samples were taken at the indicated times and processed for flow cytometry analysis. Data are mean ± SEM from 3 to 5 experiments. *, p < 0.05; **, p < 0.01; ***, p < 0.001 determined by paired Student’s t-test. (B) Cultures bearing PHO89-GFP and GAS1-GFP constructs were monitored by fluorescence microscopy after growing at normal pH (5.6) or alkaline pH (8.3) for 4 h