Molecular responses of microbes to environmental pH stress.

Publisher Summary This chapter reviews the ways microorganisms respond to pH stress focusing primarily on molecular aspects of adaptation in bacteria. The requirement for co-inducer molecules is frequent among pH-regulated genes. Most pH-stress protection systems include a mechanism for sustaining cytoplasmic pH and many inducible systems offer crossprotection to other stresses. Knowledge of pH-controlled gene expression results in improved biotechnologies necessary for producing recombinant DNA products under special conditions and for the delivery of live recombinant vaccines. Studies of the molecular responses to pH stress provide insight into the pathogenic processes and ultimately lead to better vaccine development or antimicrobial targets. Knowledge of pH-stress survival mechanisms also lead to the construction of hardier strains of root nodule bacteria that will better survive soil acidity and improve crop yields. New insights provided by recent advances in molecular genetics have rekindled interest in this important aspect of communication between microorganisms and their environment.