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MirVana + RNAlater white pellet? - What is the White pellet after mirVana extration. (Dec/17/2009 )

I have recently been storing cells in RNAlater and then isolating total RNA using the MirVana kit however I see a white pellet after I isolate my RNA. What is this white pellet?
The supernatant is 57.22ng/ul RNA with a 260/280 of 1.95, 260/230 0.66 and the 340 Raw is 0.041.
When I re-suspend the white pellet the conc RNA rises to 87.60ng/ul, the 260/280 goes down to 1.68, the 260/230 is still 0.67 and the 360 raw increases to 1.950. Could this be linked to the fact that I preserved my cells in RNA later?

Should I remove the supernatent and use this for my qPCR?


-Stuart Meiklejohn-


I have no experience with RNA later but have had a white pellet after mirVana extraction. I used to think it was because of a high yield of RNA was recovered but I have had it recently wherby I didnt notice it until after I nanodropped the sample, resuspended and only found a slight change in concentration and decrease in 230 ratio.

I think the wash solutions were getting old as it occurred when solutions were low.


I have experienced this with two new kits so i don't think it is the age of the solutions. I also have a white pellet when I isolate low amounts of RNA (eg 5ng/ul).


-Stuart Meiklejohn-

That is strange. I'll keep an eye out next time I extract. I would suspect from the 260/280 the pellet contains protein. Perhaps phone ambion (ABI) to see if they could advise with extra wash steps.