FIG 2.

Transcriptional response of the rpoS mutant after 24 h in water. The global gene expression profile of the rpoS mutant was compared to the WT strain after exposure to DFM for 24 h. (A) Hierarchical clustering of genes showing a ratio to control value of ±2-fold and a P value of ≤0.005. The normalized signal intensity is shown. The cluster of genes induced in the rpoS mutant is shown by a red line; the cluster of genes repressed is shown by a green line. (B) Cluster of orthologous group (COG) analysis of the microarray data. (C) RT-qPCR was used to confirm the expression of genes related to translation (50S ribosomal protein L25 gene, lpg0002), replication (DNA polymerase III gene, lpg2652), and transcription (rpoA, lpg0354). Strains are described in Fig. 1. The data are presented as means of three biological replicates, and the error bars represent the standard deviations. Since the data represent a ratio against the WT strain, we used the nonparametric Mann-Whitney test to assess statistical significance. *, P ≤ 0.05.