Which bacterial stress response is activated in acidic environments?
Acid tolerance is vital survival strategy for enteric bacteria such as Escherichia coli, Salmonella Typhimurium and Shigella flexneri that must traverse gastric compartment where pH can fall to 1-3 and organic acid stress in intestine. Enterobacteriaceae deploy multiple amino acid decarboxylase antiporter systems for pH homeostasis. Under acidic conditions, inducible decarboxylases such as CadA lysine decarboxylase, AdiA arginine decarboxylase and GadA/B glutamate decarboxylases consume an intracellular proton during decarboxylation of substrate to produce cadaverine, agmatine and gamma-aminob
Ref: Prescott's Microbiology, 11th ed., Chapter 7: Acid Stress Response and CadB Decarboxylase System.
