CELLULAR SONIC SIGNALS REGULATING the GROWTH of NEIGHBORING CELLS

Cells promote the proliferation of neighboring cells under a stress condition by emitting sonic signals. These signals observed using Bacillus subtilis, yeast and seedlings of Vigna mungo as signal donor and Bacillus carboniphilus, E. coli, yeast and developing fish eggs as signal recipient, could be transmitted from cell to cell through a 0.5-2mmiron barrier (JGAM, 42, 315-323 [1996]). Sonic waves generated with a sonic device at frequencies of 612, 18-22 and 26-40kHz promoted the growth of B. carboniphilus. Similar responses were also observed in E. coli. Moreover, sonics from 7 to 43kHz with peaks at about 9, 19, 29 and 37kHz were detected from cells of B. subtilis by using a sensitive microphone. The strong correlation between the frequencies of sonics promoting the bacterial growth and those emitted from B. subtilis supported that the sonics function as growth-regulating signals. Sonic signals may be emitted from cells by a mechanical process causing expansion and contraction of cellular structures and responded to by a mechanism similar to those used for the acoustic senses in higher organisms.