Best storage temperature for samples – serum, protein, tissue, DNA, RNA – Archives (Feb/02/2009 )
Due to spatial limitations in our lab freezers i want to reorganize my samples. can anyone of you tell me where different kinds of samples should be longtime stored?
-20Â°C, -80Â°C, -196Â°C…
Tissue Sections on Slides
Thanks for recommendations!
Why don’t you just keep them at the same temps. where they are stored right now. Even if you reorganize you shouldn’t put them into different freezers. Sounds like an exam question to me 😉
I help you anyway:
– DNA: Plasmids at -20C, Genomic at 4C. DNA can fall out of solution if stored at -20C. With plasmids that is no problem because you can vortex them and get them back into solution. Genomic DNA is dangerous to vortex because you might break the DNA
– RNA: Is less stable than DNA so we store it at -80. But you should be able to store it at -20C too
– Bacteria: -80C
– Serum: -20C
– Protein: – 20C
– Tissue: Depends. Ours are formalin fixed so we leave them in the fridge. Flash frozen samples in liquid nitrogen
-4`C — Tissue section on slides
-20`C — Serum, DNA, RNA, protein extracts
-80`C — Bacterial strains (in LB),
-196`C — Tissue
Along the same lines, I have been storing my protein samples, boiled in sample buffer at -20 degree. I have just been told that I shouldn’t do this and samples should be stored at 4 degree. I ran fresh samples, got results, re-ran the same samples that I stored at -20 and got the exact opposite results. Same samples, same antibody dilutions, same everything, OPPOSITE results!! The only thing anyone can think of is that the protein precipitated in the freezer and I ran aggregated or precipitated proteins. I did forget to reboil the sample but it sat out at room temp for awhile and I didn’t see any precipitated SDS. Could this have been the problem?
how long shelf life of protein extract (supernatant) in -20?
should it be stored in -80?
xiehanz on Mar 10 2009, 05:10 AM said:
should it be stored in -80?
Cell or tissue extracts in RIPA or similar buffers are best stored at -80°C, to get usefull results out of a Western blot do not store for more than one month at -20°C.
Antisera and purified antibodies do store well at -20°C or even at 4°C as long as there is no contamination (in one lab where I worked they sometimes had problems with yeasts growing in hybridoma supernatant despite being careful about sterility and keeping them all the time at 4°).
rkay447 on Feb 3 2009, 05:59 AM said:
we always do protein storage at -80 C and in small aliquots. taking out proteins now and then from the forzen state may lead to their degradation due to persistent thawing and freezing. to prevent this, we also add glycerol to our protein prep. however, to keep samples for running on gel, u can add the SDS dye and keep it at room temp. or at 4 C for days together.
I work with the conditions that UGA80 talk abaout, but I have a specific question.
I understand the reason why it should be avoided to vortex gDNA. On the oder hand, why do you store your gDNA samples at 4ºC? And how long do you store it there?
I store my gDNA (and DNA in general, purified PCR products, plasmids, primers) in fridge only for short-time storage, we have samples ages old, that reside in -20. But the main reason is not to freeze/thaw the DNA repeatedly when I’m using it all the time for a week or two. They are all in 10mM Tris pH 8, or TE. I don’t vortex any of it when I take it out of the freezer, I tap it with a finger to mix it and spin.
T store the serum and bacteria 20 and 80c temperature is needed.