Circular cassette imprint on membrane - (Apr/12/2008 )

Hi,

I recently ran and transferred two gels in the same apparatus. One came out fine while the other had only partially distinguishable bands, but more noticeably black circular imprints from the cassette! Has anyone else had this issue or know what caused it? Thanks in advanced!

I have never had good luck with running two membranes at the same time. We always have some protein that runs off of the first membrane (one that comes out ok) that bleeds through onto the second creating really splotchy, unuseable blots. Maybe you are getting te circles because that is where the cassette is open to the solution and therefore where the loose protein can get deposited. When in doubt, just run one at a time, or use separate boxes for each.

Do not allow any airbubbles in the beween the membrane and gel , I used to trasfer 4 gels at a time , i did not get this problem
First use fresh buffer(check methanol content)
use good whatman filteres(supprotive membranes use 3 to 4 in between)
Run for longer time

Finally is ur tranfer is wet or dry
if it is dry do not allow the run for more time use good quality membranes

correct me if iam wrong