Are E.Coli feeling good with music ?

LARROUY Nicolas

20/09/2016

      Well, actually, my true question is « Can specific acoustical frequencies increase the growth rate of E.Coli ? », but it seems funny to imagine them dancing on the rythm of the music... However, this is quiet an interesting question because if the answer is yes, it would allows scientist to grow huge population of Bacteria faster than in normal conditions. We already know that in a 37° media, with enough food, E.Coli can divide each 20/25 minutes, giving two new bacteria. Maybe some music could reduce this time to 18, or maybe 15... Hahaha.

My experiment could be linked with experiments conducted by Raphael Bastos Mereschi Aggio, Victor Obolonkin, Silas Granato Villas-Bôas (1), wich says that yeast are sensible to sonic vibrations, even if it is still obscur how does it interfier but... It does.

Ok, stop blablating, let's go on it !

Pro-Pro-Pro... Protocool !!

       The question is, how can we proove that growth rate of E.Coli increases specifically because of some sound frequencies ? Well, cultivating different populations, from the same tube, in conditions differing only with the exposition to sound, is for me a very good way to proove that sound have made them growing faster. And this is what I did. I exposed three populations with three frequencies, during the same time, in the same conditions, with the same food, with... Ok I stop here.

Each 20 minutes, I was puting my populations in a spectrophotometer, expecting to see an increasing of the Absorbance with the time. Sometimes, it was quiet slow, but for one population, it has been faster than for the others.

      As you can see on my graph, the population exposed to the 10.000 Hz frequency have grown much faster than the others ! This is a proff that bacteria have the beat !

Ok, let's go slowly. This graph shows the growth rate of 4 populations of E.Coli, as a function of the Sound Frequency with which they've been exposed. As you can see on the y axis, there is a Negative control, a population exposed to no sound, with a certain growth rate. For the 400 Hz population and for the 5.000 Hz, it is almost the same, so it's hard to conclude anything with theses populations. However, the growth rate of the 10.000 Hz population is obviously much higher than the three other populations.

How I have calculated this growth rate :

   -I had 13 values of Absorbance, for each populations, at the end of the growth.

   -I made a linear regresion between the first, and the last value.

   -I took the slope of this regresion → This is my growth rate.

      So, I can conclude that some frequencies can help bacteria growing faster, but I still have absolutely no idea how does it work. However, we can reproduce this experiment with more frequencies, and not only located in the audition spectrum.

If You Want To Know More :

● Aggio, R.B.M; Obolonkin, V. and Villas-Boas, S. G. 2012. Sonic vibration affects the metabolism of yeast cells growing in liquid culture: a metabolomic study. Metabolomics 8:670–678.

doi:10.1007/s11306-011-0360-x >>>

● Lilianna Cabrera, prezi.com, “How does music affect bacterial growth ?” 12/05/2015

● Guy Damman, “Microbes and Mozart”, The Guardian, 06/06/2010

● My e-mail adress : nicolas.larrouy@cri-paris.org