Re-using hybridisation solutions containing double-stranded probes?

[Glen Shearer]

We often reuse ds DNA probes from old hyb soln (0.5 M NaPO4, 5% SDS).
We just put the tube containing the hyb soln in boiling water for
about 10 min. and then pour it onto the blot that has been
pre-hyb'd for about an hour.

I recall one time that I tried this with a 10 day old 32-P probe
stored at room temp in the old hyb soln and could still see a 
single copy gene on a 5 ug/lane yeast genomic southern!

Once it even worked when a grad student in the lab forgot to boil
the old hyb soln'!!  But.....it took about 10 days against film
with screen at -80C !!

It's certainly not as good as a fresh probe in TE, boiled then
snap frozen....but if the probe is fairly hot and there is a
good amount of target on the blot, it's a great time saver!!

Regards,
Glen
[gshearer at whale.st.usm.edu]