10 replies to this topic

[Bassaml7]

I mean what happens Chemically ? I hope someone can explain that , even in simplified terms. ( Please cite a reference if possible ) .

Edited by Bassaml7, 25 September 2009 - 08:07 AM.

[fishdoc]

Bassaml7, on Sep 25 2009, 11:06 AM, said:

I mean what happens Chemically ? I hope someone can explain that , even in simplified terms. ( Please cite a reference if possible ) .

I'm not sure. I've stored bacterial genomic DNA at 4C for well over a year. Still good for PCR, anyway.

[milla]

Hi,
I bought genomic DNA and the company suggest to store at 2-8 C.
For now it is still working fine!

[Bassaml7]

Thank you for your replies . I don't want to Freeze DNA to avoid repeated Freeze\Thaw cycles plus the need for vortexing .

How about Primers ? Can I also store aliquots of my primers safely at 2-8 at least for a month or so ?

I also wonder if I can store dNTP aliquots that are in current use at 2-8 for less than a month to avoid repeated freezing and thawing.

Edited by Bassaml7, 26 September 2009 - 02:32 AM.

[hanming86]

I read this in qiagen .

SO storing DNA in H2O would be risky for long term in 2-8. the pH of H2o drop without buffering system thanks to CO2 in the air. Acid hydrolysis in this matter coz the DNA to degrade.

[Bassaml7]

hanming86, on Sep 26 2009, 03:36 AM, said:

I read this in qiagen .

SO storing DNA in H2O would be risky for long term in 2-8. the pH of H2o drop without buffering system thanks to CO2 in the air. Acid hydrolysis in this matter coz the DNA to degrade.

I would never store any of PCR reagents in just water . I always use 1X PCR buffer for dNTP and TE for Primers/Template DNA . Though some people dilute dNTP in water . I think using a solution buffered at the "safe" pH is good general practise.

Edited by Bassaml7, 26 September 2009 - 07:02 AM.

[gleb.kudr]

Bassaml7, on Sep 26 2009, 02:03 AM, said:

How about Primers ? Can I also store aliquots of my primers safely at 2-8 at least for a month or so ?[/color]

Depend on concentration and primer length. More dilution and less length are both affected primer stability. 10nmol/40 b.p. worked normally after 2 months store at 4C.

[Bassaml7]

gleb.kudr, on Sep 26 2009, 08:43 AM, said:

Bassaml7, on Sep 26 2009, 02:03 AM, said:

How about Primers ? Can I also store aliquots of my primers safely at 2-8 at least for a month or so ?[/color]

Depend on concentration and primer length. More dilution and less length are both affected primer stability. 10nmol/40 b.p. worked normally after 2 months store at 4C.

Thank you for your reply. My primers are actually about the standard length i.e around 20 bp . I wish I can find a reference Nucleic acids Chemistry from which I can conclude all this kind of information and even understand the detailed mechanisms behind it.

[hobglobin]

Bassaml7, on Sep 26 2009, 09:00 PM, said:

gleb.kudr, on Sep 26 2009, 08:43 AM, said:

Bassaml7, on Sep 26 2009, 02:03 AM, said:

How about Primers ? Can I also store aliquots of my primers safely at 2-8 at least for a month or so ?[/color]

Depend on concentration and primer length. More dilution and less length are both affected primer stability. 10nmol/40 b.p. worked normally after 2 months store at 4C.

Thank you for your reply. My primers are actually about the standard length i.e around 20 bp . I wish I can find a reference Nucleic acids Chemistry from which I can conclude all this kind of information and even understand the detailed mechanisms behind it.

The main risk in storing DNA at 2-8 degrees is that fungi or bacteria can grow if there is any contamination (contaminated solutions or tips,...). Sometimes it happens and you don't know why, so I'd only put aliquots at that temperature and the stock in the freezer.
TE (i.e the EDTA) also helps to inactivate enzymes that cleave DNA.

[bob1]

What happens in water is termed acid hydrolysis, it does slowly degrade the DNA, however, this process is very slow and DNA should keep at 4 ˚C for quite some time.

[Bassaml7]

hobglobin, on Sep 26 2009, 12:48 PM, said:

Bassaml7, on Sep 26 2009, 09:00 PM, said:

gleb.kudr, on Sep 26 2009, 08:43 AM, said:

Bassaml7, on Sep 26 2009, 02:03 AM, said:

How about Primers ? Can I also store aliquots of my primers safely at 2-8 at least for a month or so ?[/color]

Depend on concentration and primer length. More dilution and less length are both affected primer stability. 10nmol/40 b.p. worked normally after 2 months store at 4C.

Thank you for your reply. My primers are actually about the standard length i.e around 20 bp . I wish I can find a reference Nucleic acids Chemistry from which I can conclude all this kind of information and even understand the detailed mechanisms behind it.

The main risk in storing DNA at 2-8 degrees is that fungi or bacteria can grow if there is any contamination (contaminated solutions or tips,...). Sometimes it happens and you don't know why, so I'd only put aliquots at that temperature and the stock in the freezer.
TE (i.e the EDTA) also helps to inactivate enzymes that cleave DNA.

Thank you very much that's quite helpful.