Differential expression analysis of T. thermophilus HB8 wild-type strain in response to copper.

We observed the expression profile of the total mRNA in Thermus thermophilus HB8 wild-type strain at 0 and 30 min after the addition of CuSO4. Three wild-type strain of T. thermophilus HB8 were pre-cultured at 70 degC for 16 hours 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 (1 mL) were inoculated into 250 mL of the synthetic medium and then cultivated at 70°C for 8 hours (A600 value being ~0.44). Then the 1.25 mM of CuSO4 was added into the medium, and continued cultivation. Cells were collected at 0 and 30 min time point after the addition of copper ion, and then crude RNA was extracted. The expression of each mRNA at each time point was analyzed on a GeneChip as described under Sample Description Sheet of each sample.