Philippe Lejeune wrote:
>
> Has anybody tried to assay beta-galactosidase in-situ using FDG (in
> bacterial or eucaryotic cells) ?  How to allow uptake of the fluorogenic
> substrate ? Is this substrate able to penetrate into tissues or bacterial
> biofilms ?
>
> Thank you very much
>
> Philippe Lejeune
>
> Laboratoire de Genetique des Microorganismes
> Institut National des Sciences Appliquees de Lyon
> 69621 VILLEURBANNE (FRANCE)
>
> Tel : (33) 72 43 87 06
> Fax : (33) 72 43 87 14
> E. mail : [log in to unmask]
 
Generally this probably won't work for two reasons
1.  The FDG is not particularly permeant to living cells.  There are a
few rumors floating around that if you leave it long enough with the
cells then some may get in.
 
2.  Once cleaved you end up with either fluorescein or fluorescein
mono-galactoside, but eventually just plain old fluorescein.  This stuff
leaks out of cells pretty quickly (usually less than 20 minutes)
 
What you really need is a fluorescent equivalent of X-gal, but
unfortunately I don't know of such a thing.
 
Ian