"Microsonic"
An interdisciplinary musical project inspired by microbial communication

By Ruth Schmidt, Eva van Ooij and Lucas Wiegerink, guest contributors to SciArt Magazine

Communication in biology is by definition the transfer of information from one cell or molecule to another, as by chemical or electrical signals. The most common way of chemical communication between microorganisms is quorum sensing, a mechanism that regulates gene expression in response to cell density. But microbial communication also takes place via physical interactions, including sound waves. Studies have reported that sound waves stimulate the growth of a type of bacteria in the Bacillus family (B. carboniphilus) under stress conditions. Furthermore, sound waves were detected by another Bacillus species (B. subtilis)at three frequencies that matched with the B. carboniphilus growth-promoting frequencies. Thus, is appears that the microbial microcosm is a rich sound world on its own. In the opinion article "When microbial conversations get physical" the author, Gemma Reguera, invites us to reflect on microbial communication via sounds, stating that “every particle in a cell has a unique natural frequency of vibration and therefore produces a distinctive sound, very much like voice tonality and pitch in humans.” Sound waves are generated when objects vibrate. In the studies she cites, Saccharomyces cerevisiae - a type of yeast - not only demonstrated that intracellular motions were sufficiently strong enough to propagate across the rigid cell wall, but that they could also generate reproducible acoustic signals.

Research about microbial communication via sound signals has only received limited attention due to its technical challenges. Even though electronic devices that are capable of detecting sounds on microscopic length scales get more advanced every day, the technique is still in its infancy. It is already possible to hear the sound of a large group of microbes - which sounds like white noise - but the devices still need to be developed further to be able to hear the sound of single microbes.

Art meets science – Microsonic 
Both artists and scientists seek to understand aspects of the complex world around us. Despite this common ground, artists and scientists are too often separate in their endeavors. Music, the ultimate abstract art form, is not tied to specific, meaning-laden images, and can therefore easily bridge the gap between the arts and the sciences. Recently, several attempts have been made to interpret microbial sounds in the form of music for the public. One such project from Energy Bending Lab translated the bioelectrical activity of different organisms, such as slime mold and E. coli, into sound. Our project adds to these developments by exploring what a musical composition based on a microbial conversation could sound like.

Microsonic is a soft musical piece, giving the audience the feeling of a hidden sound world. The public is invited to join on a sound journey into the human body. The microbial world slowly fades into their world. A tape with reproduced sounds stemming from the human body is added to the composition to give the translated communication of microbes a real context. The sound journey starts off with a kind of white noise – unclear, almost inaudible – making the listener wonder what it might be. It is the sound of blood streaming through a vein. Then the zooming in begins: more and more, internal body sounds are heard, including the creaking of human nerves. But also, by zooming in further, the sound produced by microbes is heard. Here, the musicians come into the picture. The playing instruments symbolize the several sound signals that microbes use to communicate. First they play soft airy sounds, representing the sound produced by millions and millions of microbes. Slowly the listener gets introduced into their microscopic world and more and more pitched signals become distinguished, representing the sound produced by single isolated microbes. First these signals are short, but as we zoom further, one hears longer ones as well. The microbial sound world becomes richer and richer; higher and lower pitches occur and the dynamic contrasts intensify. When listening carefully, one will hear that microbes make connections and communicate by taking over each other's signals. So does the musician – based on live improvisation. It is at this moment that you, as a human being, can get a glimpse of the communication of microbes and maybe even feel part of their conversation. The composed journey ends with a collective "vibrational mode." This occurs when a certain group of microbe cells are "in tune." The similar vibration of their signals will amplify naturally to such an intensity level that it can prey other cell groups; a very effective method for cells to increase the nutrient availability .

The challenge for the composer was to go beyond from thinking in only melodies and chords. Microbial communication via sound signals is not a musical process; still it produces patterns and sounds that are musical. As a result, the composition changed towards creating a number of frameworks in which the musicians had freedom of movement and became part of the creation process. The subject of communication lends itself very well to this way of making music. The musicians improvise while listening and reacting to each other; they need to communicate to let it work.
 
Concluding remarks 
Our project is an example of how artists and scientists, both being driven to understand and express the complex external world, can reinforce each other. It is exactly this what makes interdisciplinary collaboration particularly interesting, since it questions the usual approach and way of working. But there is more to it: interdisciplinary collaboration can support inspiration in each other’s work and reinforce the expression of the complex mechanism in our (microbial) world towards the public. All we can recommend is: step outside, open your eyes and take the risk to look outside your usual box.

Listen to an excerpt of Microsonic here:

About the authors

Ruth Schmidt recently finished her PhD in Microbial Ecology at the Netherlands Institute of Ecology in Wageningen, The Netherlands where she studied microbial communication via volatiles. Eva van Ooij is a musician who also has a background in European and international Law and works at Maastricht University, and Lucas Wiegerink is a composer who studied at music conservatories in The Hague, Amsterdam, and New York. 

References

- Larsen PE (2016) More of an Art than a Science: Using Microbial DNA Sequences to Compose Music. Journal of microbiology & biology education 
17: 129-132.
- Matsuhashi M, Pankrushina AN, Takeuchi S, et al. (1998) Production of sound waves by bacterial cells and the response of bacterial cells to sound. The Journal of general and applied microbiology 
44: 49-55.
- Reguera G (2011) When microbial conversations get physical. Trends in microbiology 
19: 105-113.
- Waters CM & Bassler BL (2005) Quorum sensing: cell-to-cell communication in bacteria. Annual review of cell and developmental biology 
21: 319-346.