Counting GFP colonies

Bernard Murray bernard at elsie.nci.nih.gov
Tue Jan 7 13:44:33 EST 1997

In article <32D14DE4.6D81 at umich.edu>, pboucher at UMICH.EDU says...
>I am interested in counting colonies that stably express GFP for 
>cytotoxicity assessment studies.  I want to be able to count colonies 
>that lack and express GFP.  Is there an easier way of doing this than 
>counting the colonies under a fluorescent microscope?  Perhaps some sort 
>of fluorescent dish scanner.  I would appreciate any input.  Thank-you.
>        Laura Zerbe Rubsam

Could you get away with lysing the plate of cells and then comparing
the fluorescence (in a fluorimeter) with protein or DNA concentration?
You could then relate this to the results of GFP-negative and GFP-fully- 
expressing cells (measured in separate determinations).
	This is clearly the quick'n'cheap way of doing it.  For more
precise results you could use a FACS if you have one available.
Has anyone tried modifying a Coulter Counter...?

Bernard Murray, Ph.D.
bernard at elsie.nci.nih.gov  (National Cancer Institute, NIH, Bethesda MD, USA)

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