Hi all. I am trying to calculate the concentration of phages purified by the PEG method. How should I proceed?
I would like to express the result in nM/ml
thanks
The traditional method ,the final PFU for each plate is n×10×dPFU/ml.where n is the number of plaques observed and d is the value fro dilution series.
Ref:https:// barrick_Lab .org>view lab.
I concur with with Salameh Barhoom response that you should just determine the PFU by doing a titer of your purified stock. But do note this will give you the number of viable phages, there might also be a significant number of non-viable phages in the mix, so whether that matters depends upon what you are doing.
If you wish to express in nM/ml then it is merely a matter of math manipulations.
I have the same question, but I don't really understand the answers of Salameh and Michael. The concentration that both of you said, are expressed in PFU/ml. But If Oscar needs nM, I think he have to use the extinction coefficient and the optical density of the purified phage.
Michael said it is merely a matter of math manipulations, can you please explained this for me? I don't understand.
Michael J. Benedik Salameh Barhoom Oscar Otero Alfaro
Thanks in advance
That is a good question Fateme Sharifi and you just need to go back to early chemistry which we all forgot, essentially Avagadro's number. 1 mole of anything is 6.02x1023 molecules (or items, or phage, or people) etc. So 1M phage would be a titer of 6.02x1023 PFU/L (Or 6x1020 PFU/ml). And 1mM would be 6x1017 PFU/ml etc. So it's just math knowing your titer and Avagadro's number.
We never think of things this way because we almost never know the actual number of molecules or items we have, but in this rare situation we have the number, but not the normal "chemical" information.
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