Fluctuation of transcriptional levels of heat shock protein genes through a culture period in strains 17 and 17-2. Total RNA was isolated from 6, 12, 18, 24, and 30 h-old cultures of strains 17 and 17-2, and the relative expression levels of these genes were recorded by the strain using real-time RT-PCR. The expression levels of these genes were fluctuating in strain 17 but not in strain 17-2. Data are representative of two independent experiments. dnaK: PINA1058; dnaJ: PINA1756; groEL: PINA1797; groES: PINA1798; clpB: PINA2006.