Differential expression analysis of T. thermophilus HB8 wild-type strain in response to addition of silicic acid and removal of iron.

We observed the expression profile of the total mRNA in Thermus thermophilus HB8 wild-type strain at 60 min after the addition of silicic acid and removal of iron. Three wild-type strain of T. thermophilus HB8 were pre-cultured at 70 degC for 16 hours in 3 mL of TM medium containing 0.8% polypeptone, 0.4% yeast extract, 0.2% NaCl and 1% Castenholz' basal salt solution, 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°A600 value being ~0.60). Then the 600 ppm of silicic acid was added into the medium or removal of iron, and continued cultivation. Cells were collected at 60 min time point after the change of medium, and then crude RNA was extracted. The expression of each mRNA at each time point was analyzed on a GeneChip.