about penicilin streptomycin - (Aug/11/2005 )

hi all, my colleague told me that a tube of penicilin streptomycin will be degraded when it had been incubated at 37 degree overnight, is he correct about this please? I don't think there is an enzyme or other stuff to give such an effect, but I am not sure. Please help me out, thanks so much.

Hi,
I cannot say for sure, but I hope not!!!! That would mean that the P/S on my cells has to be changed every day to be effective right??? If I had a stock of P/S that was accidentally left at 37C I would not use as a stock because it may not have the right working concentration anymore, but I don't belive gross degradation has occurred... Hopefully someone else can confirm.

Threre you have a great point, thanks for your advice. Cheers!

Well, I am not an expert on antibiotics, but I believe most of them are unstable molecules. If they were stable, there would be no reason to store them @ -20°C like you can with other stock solutions.

But, I don't add any antibiotics to my cell growing medium. I really believe that if the bacteria are in there, antibiotics will not get them out. Other people here who still use the antibiotics also say that if they notice they have contamination they never could get the bacteria out, even when trying a whole lot of different antibiotics, so were they by accident a mutli-resistant strain? I believe it to be a lot better to be very cautious and work very sterile and regularly check the cells for anything suspicious.

I just throw away my cells if they are contaminated with anything and thaw a new stock of cells (just had to do this once).

hi
peni strepto are molecules that are quite stable at 37°C. But in the medim of cells, it's recommended to change them with the medium in order to keep quite equal amount of P/S during all exp, and for repetitive exp.
37°C O/N will not affect your P/S drastically. that are the basics : If it's an aliquot, throw it away. If it's your stock solution, do with it.
For myself, i would use it for my exps.
fred

I am just asking, to which cell culture it is recommended to add peni/strepto? To all? Neighbour lab which deals with Vero cell does not add this antibiotics...

Wow folks, thank you so much for your replies. I did not know what to reply. Anyway, now I think I know a little more of how to deal with this situation. Thanks again.

I added antibiotics to all my cell lines except some Xanopus cells.