Hi All,
I am trying to heat-kill some bacteria for an experiment, but do not want them to rapture (ie. maintaining their cell wall structure). does anyone have a quick and easy-to-do protocol for this, please?
Hi!
Do they have to be necessarily heat-killed or can they be killed by different means? If so, you can consider fixing the cells with PFA. This maintains structure, while definitely killing the cells.
Hi Priscilla,
The temperature and length of heat treatments for killing bacteria depends on the bacterial species you are using, and on the growth conditions. Robustness of bacterial envelope greatly varies across species (i.e. between Gram- and Gram+). Moreover, for bacterial species able to sporulate, heat treatments are necessarily harsher and longer, if one wants to eliminate all viable spores. The physiological status of the bacterial population can also affect thermal sensitivity; for instance, actively replicating bacteria vs bacteria in stationary phase or in biofilms can respond very differently to heat.
As a reference, for Escherichia coli happily growing at exponential phase in rich medium, 5 minutes at 70 degrees might suffice to kill the entire population without affecting cell structure of most bacteria (there will always be some lysis).
What I would do is checking different temperatures and treatment lengths for your specific bacteria in the concrete conditions you are planning to use, and then check cell viability (by plating) and integrity (by microscopy), in order to choose the conditions that maximize killing without significantly affecting cell integrity.
Good luck!
Thank you, Catarina Nunes , that was my original plan, but after running a few pilots, I notice that the PFA itself is very toxic to the flies so it only compounds my unknowns..
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