Potential Role of Calcium Lon in Mediating the Response of Escherichia Coli to Audible Sound Stimulation

Previous studies from our laboratory have indicated that audible sound field stimulation can significantly affect E.coli growth and metabolic action, which can enhance or inhibit the growth of Escherichia coli (E.coli), and the effects of sound field on E.coli growth depended greatly on the intensity and frequency of sound field. However, very little efforts have been put forth in studying the potential mechanism of bacterial cells responses to audible sound stimulation. In this paper, the potential role of calcium signaling in mediating the response of E.coli to audible sound stimulation was firstly reported. We found that audible sound wave stimulation could evidently enhance total intracellular Ca2+ content. And the lack of calcium ion in medium significantly alleviated audible sound wave biological effects. Moreover, by adding appropriate level of calcium chloride to the LB medium contained 1.2 mM EDTA, the promotion effect of audible sound wave to E.coli growth was gradually resumed. On the basis of these findings, we speculate that calcium signaling may play an important role in mediating the response of E.coli to audible sound stimulation.