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Sherie Masse smasse at tigger.cc.uic.edu
Tue Aug 18 18:32:45 EST 1998

I have recently received a barrage of emails from people responding to a
letter which was posted on this newsgroup and attributed to my email
address.  I, however, did not post the original inquiry, which was:

Does anyone have an idea as to why I sometimes get a "pop" when using a
Biorad electroporation setup?  It sometimes happens and can blow the
sample right out of the cuvette.  It is rather loud and scary besides!

Here are the various responses I have recieved, for whomever is
searching for the answer.  If anyone else would like to respond to the
electroporation question, please post them on the newsgroup so that the
person who is interested in the answers can find them:

 "Marc F. Schwartz" <schwarmf at BIOMED.MED.YALE.EDU>
i was told that if the salt content is too high in the sample, the
electrodes will arc causing the bacteria to splatter...  when i prep
electrocompenent bugs, the final solution is 10% glycerol in milliQ pure

water, and i sometimes precipitate the DNA if i'm worried that the salt
content in the DNA solution is too high...  (ppt as per the normal EtOH
ppt with a small amount of glycogen as carrier if the DNA concentration
too low, resusp in milliQ H2O, transform...)

good luck,
--marc s.

Srinivas Merugu <smerugu at UH.EDU>
Hi! I know of someone who had a similar problem once. I think it was
the cells she used were not suitable for electroporation. I think you
check if the cells you are using can withstand electroporation.

Deb Court <dcourt at cc.UManitoba.CA>

It is rather scary! Do you find yourself pressing the buttons and
the other way, waiting for a pop!?

I think it is most often due to "not perfectly clean cuvettes". It
helps to wash the cuvettes in ethanol (70%) and perhaps even clean the
inside with something very soft like a cotton swab. I think that the
composition of the mix can also affect things, but if its only
then that's not likely the cause.
Good luck!

It is most likely due to the salt concentration in the ligation mix, or
whatever is being electroporated. It happens with other than Biorad
instruments as well, BRL etc. One has to be meticulous re salt. For
ligation mixes, precipitate with EtOH and wash carefully with 70% EtOH.
Dilution may suffice but less consistent. This should help.

Dr. Ronald E. Pearlman           ronp at yorku.ca
Professor, Dept. of Biology
Director, Core Molecular Biology Facility
York University
4700 Keele St., Toronto, Ontario, Canada M3J 1P3
Phone:416-736-5241; FAX:416-736-5698

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