I'm looking for an example of bacteria that could receive ultrasound (at any ultrasound frequency) signal and possibly perform some (re)action afterwards.
I'm going to post a quick answer here, really a thought piece.
Usually to detect a sound wave you need a sounding board about the wavelength of the sound.
Bacteria are on the order of a few microns in length.
Ultrasound frequencies range from 2 to 200 MHz (and up I assume).
So only on the very high end of the range. If bacteria make sound though, they probably are on this frequency range.
I wonder if this has been looked at? Not sure it has. While in biology you never say never - if a bacterium really needs to pick up a wave it might have a clever adaptation to do so, but in the 100MHz + frequency range seems more likely.