Morbidostat – for antibiotic resistance evolution experiments

[Oscar]

Hello ,

I am very interested in acquiring a Morbidostat (a device that can tune growth rate by dynamically adjusting antibiotics concentration in the culture medium). Do you think that it would be possible to adapt Chi.Bio device for this purpose? Perhaps using one of the inducer pumps to inject medium supplemented with antibiotics into the bioreactor?
Otherwise, do you know any company or developer that could provide us a validated Morbidostat?
My best regards,

Oscar Pereira Ramos (CEA, France)

PS: One detailed example of a Morbidostat device can be found in the following paper: https://www.nature.com/articles/nprot.2013.021

[harrison]

Hi Oscar,
Yes, the system can very easily be re-programmed to do that. In fact, in the past we have tested it on control of microbial communities in which multiple species grow together, and two different media are mixed dynamically to regulate their relative growth rate.
Such a control system can easily be implemented in the software (with the “custom program” feature), and enables protocols like the one in the paper you linked to be run.
Typically I would use a setup with one jar of normal media, and one jar of media + antibiotic, and mix the relative inflow fraction from each. This way you avoid having to dispense very small and precise volumes (e.g. as would be required if you had a jar of just concentrated antibiotic not mixed with media).

[Oscar]

Hi Harrison,

Thank you for your reply. I am seriously thinking about buying some Chi.Bio system for our team (great job by the way…) but before I would like to have an overview about the implications of re-programming the system to our applications. I am trying to figure out if I could do it myself or if I should put some collaboration in place. Chi.Bio website suggests to check github readme file for instructions about creating custom programs and this file redirects me to the Chi.Bio website. Where can I find the “beginner’s guide” that is mentioned on the website?

[Constant]

Hi all,

Oscar, I am currently developing a custom program for directed evolution which would have a similar purpose, injecting a chosen mix from two bottles (one with growth media, the other one with stressing media).
Coding a custom program is doable if you are comfortable using python, but be prepared to spend quite a lot of time understanding how Chi.Bio has been coded, because I couldn’t find any documentation on the code.
I just managed to take full control of the pumps yesterday, I’ll let you know where things are going when I can find more time to work on the code.

Kind regards,
Constant (also in France)

[Oscar]

Hi Constant,

Good to know that there is someone working on a similar program. Thank you for your reply and please keep me posted.

Oscar

[harrison]

Hi both, apologies for the lack of documentation thus far; I need to work on a readme for the Github! I recently went through and added comments throughout as a first step, and at some point soon will work on a full-on readme, ideally as a precursor to a more fully-fledged API. If you have any specific questions about implementing your custom programs in the mean-time please let me know!
Harrison

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