Fig. 1

Glycogen and trehalose accumulation in the Δpal mutant strains and in the wild-type strain at normal growth pH (5.8) and alkaline pH (7.8). Mycelia samples from the wild-type and Δpal mutant strains cultivated at pH 5.8 and 30 °C for 24 h and shifted to pH 7.8 for 30 and 60 min were used for glycogen and trehalose quantification. Glycogen was digested with α-amylase and amyloglucosidase after precipitation with cold ethanol and trehalose was digested with a partially purified trehalase from Humicola grisea. Free glucose was quantified and the glycogen and trehalose concentrations were normalized to the total protein concentration. The asterisks indicate significant differences compared to the wild-type strain at the same condition (Student’s t-test, P < 0.01). All results represent the average of at least three independent experiments. Bars indicate the standard deviation from the biological experiments. 0, sample before pH shifting (control sample, 24 h of growth at pH 5.8)