FIG. 2.

Heat maps comparing the expression profiles of 284 stress-related genes in Sakai (SK) and TW14359 (TW) under chlorine and hydrogen peroxide treatments. Genes that are functionally associated with bacterial stress response were chosen for hierarchical clustering analysis. The fold change value for each gene was converted to the log₂ value. A pseudocolor scale from red to green shows log₂ values ranging from 3.7 (equivalent to 13-fold upregulation) to −2.3 (equivalent to fivefold downregulation). The genes were divided into six functional groups, A to F. (A) Genes directly involved in environmental stress. (B) Genes encoding the Fe-S assembly and repair system, the thiol-redox system, and other Fe-S cluster containing proteins. (C) Genes involved in cysteine synthesis and transport. (D) Genes encoding heat shock and cold shock proteins. (E) Genes encoding outer membrane proteins and transporters. (F) Virulence genes and biofilm-related genes.