Figure 5. Glycogen accumulation and gene expression during combined pH and heat shock stress.

Glycogen and total RNA were extracted from wild-type mycelia cultivated at pH 5.8 and 30°C for 24 h and then shifted to pH 5.8, 4.2 and 7.8 at 45°C for 30 min. After 30 min, the remaining samples were transferred back to the physiological temperature (30°C) at the three pH conditions and incubated for different times (RE, recuperation). (A) Accumulation of glycogen. (B) gsn and pacC gene expression. Total RNA (15 µg) was separated by electrophoresis in a denaturing formaldehyde gel, transferred to nylon membrane and probed with the α-³²P radiolabeled 678 bp gsn cDNA and 639 bp pacC cDNA fragments (gel autoradiographies). The 28 S rRNA was used as a loading control after ethidium bromide staining. The results shown are the average of at least three independent experiments. 0, cell samples before pH shifting (control).