Relative genes transcript level of S. thermophilus cells exposed to a heat stress. Total RNAs were extracted from stationary phase cells of S. thermophilus LMG18311 (dark gray bars) and its isogenic Δrgg
mutant (light gray bars) grown in CDM at 30°C until stationary phase and then exposed 30 min at 52°C (heat stress condition). Data are presented as the mean +/- standard deviation of the gene transcript levels measured from 3 independent experiments done in duplicate. Student's t test: *, p < 0.001.