Bacterial stress response due to acoustic cavitation

Abstract

E. coli bacteria that have been genetically engineered to emit visible light when they are stressed provide a means to study the mutual interactions of ultrasound, bubbles, and bacterial cells [Vollmer et al., Appl. Environ. Microbiol. 64, 3927–3931 (1998)]. Stresses such as protein damage, DNA damage, oxidative stress, and membrane perturbation produce differential light output in different strains of bacteria exposed to similar acoustic cavitation fields. The relative severity of each of these stressors, as determined by the luminosity per surviving cell, suggests the relative importance of each damage mechanism. Besides giving insight into cavitational mechanisms, the results suggest the parameters most useful for acoustic purification of water.