Time course of the mRNA expression in wild-type Thermus thermophilus HB8 strain grown in a rich medium (labeling:Affymetrix)

In order to observe altered expression profile of wild-type T. thermophilus HB8 strain grown in a rich (TT) medium at 70°C. we analyzed time-dependent mRNA expression profile of the total mRNA from the strain, which corresponds the logarithmic phase to the early stationary phase. Three wild-type T. thermophilus HB8 strains were pre-cultured at 70°C for 16 h in 3 ml of TT medium containing 0.8% polypeptone, 0.4% yeast extract, 0.2% NaCl, 0.4 mM CaCl2, and 0.4 mM MgCl2, which was adjusted to pH 7.2 with NaOH. The cells (2 ml) were inoculated into 1 liter of the same medium and then cultivated at 70°C. Cells were collected after 180, 240, 300, 360, 420, 480, 540, 600, 680, and 760 min, and then crude RNA was extracted. The expression of each mRNA at each time point was analyzed on a GeneChip.