Time course of the mRNA expression after phage ϕYS40 infection in crp deletion mutant of Thermus thermophilus HB8.

We observed the expression profile of the total mRNA in crp (TTHA1437) deletion mutant strain of Thermus thermophilus HB8 during infection of bacteriophage ϕYS40. Keywords: time course, bacteriophage, infection, CRP, cAMP receptor protein, deletion mutant Three crp (TTHA1437) delection mutant strain of T. thermophilus HB8 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 until A600 value being ~0.8 (1.7 108 cells/ml) that corresponds to logarithmic growth phase. Then the FYS40 phage was infected to the medium at multiplicity of infection (m.o.i.) being ~1, and continued cultivation. Cells were collected after 0, 75 and 100 min infection, 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.