FIG. 7.

Sections of dual-channel images generated by DNA macroarray analysis (Sigma-Genosys). PCR-derived DNA samples for each B. subtilis gene were spotted onto nylon membranes as recommended by the manufacturer (Sigma-Genosys). Each gene or ORF is represented by one double spot. A transcriptome comparison of B. subtilis strains BR16 and BR17 in response to norvaline treatment is shown. Dual-channel images were generated by combining macroarray image 1 (exponential growth; green channel) and macroarray image 2 (10 min of norvaline stress, red channel) (see Materials and Methods). Red spots indicate transcriptional induction by norvaline treatment. Orange- and red-bordered yellow spots represent genes whose transcription was already strong under control conditions but was further enhanced by norvaline treatment. Green spots represent genes whose transcription is switched off. Some prominently induced or repressed genes are indicated. (A) RelA-dependent transcriptional repression of genes encoding r-proteins and ybxF and map (class I). (B) RelA-dependent induced genes of the ilv-leu operon (class II). (C) RelA-independent induced genes (class III). (D) RelA-independent repressed genes encoding enzymes of purine biosynthesis.