I have tried to use Genereleaser on total nucleic acid extracts to
help in amplifying viroid RNA with reverse transcriptase PCR. I
wasn't using it to actually extract from leaf tissue, but was using it
to bind inhibitors present in the dirty extracts. It did work, in
that I could only amplify something from samples which had the GR, but
I developed problems with negative controls coming up positive.
I looked at the stuff under the microscope to try and work out
what it was made of, (glassmilk/clay???) and was very surprised to
find bacteria swimming around in the matrix. I plated out 50ul onto
Sucrose Peptone agar and LB agar and incubated at 25C for 3 days.
There was significant growth, which was identified through fatty acid
analysis to be a Rhodococcus, probably R. globerulus. I made an
extract of the bacterial DNA and did standard PCR on it using my
primers , and got the same sized band as the negative control bands.
The Australian distributor contacted the manufacturer, which said
they couldn't isolate anything. So, we bought another batch. We
opened it in a laminar flow an plated out again. Same growth, same
ID, same PCR products in the negative control. I don't use it
anymore, and haven't for about 18 months now, so they may have
rectified the problem. It is interesting that they don't recommend
the product for use in RAPD PCR. I guess I was unlucky that my viroid
primers matched the contaminant.
Other people in my lab use GR happily, so it couldn't hurt to try
it. Ask for a sample first and plate some out to check, just to be