photoemulsion

[Marcel Hoffmann]

Dear netters

I'm experiencing problems using Ilfords K5 emulsion. I'm 
trying to clone a GPCR by expression cloning and I have a 
iodinated radioligand specific for this receptor. My 
testsystem is a cloned GPCR and its cognate ligand. When I 
transfect COS7 cells with my test GPCR I get high expression 
and after incubation of the transfected cells on a microscopic 
slide I can detect the positive cells by autoradiography. 
However when I dip the very same slides in a warmed (35 
degrees) photoemulsion, expose them for the same period (two 
to three day's) and develop the slides my signal has 
disappeared.

Can anyone explain to me wat is happening here.
I tried different temperatures already but that doesn't work.

thanks in advance
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Marcel Hoffmann Ph.D.
Dept. of Pharmacochemistry 
Vrije Universiteit Amsterdam
de Boelelaan 1083, 1081 HV Amsterdam 
tel: +31(0)20-4447572
fax +31(0)20-4447610 
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