DNA Spec. ques.

[lwong]

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Hey it's my first time doing research, and I am not too far in my studies. So please don't laugh if this is a silly question...I am isolating a plasmid from E.coli through microcentrifuging, etc. I need to check if the DNA is in the final tube. I know I can do so through electrphoresis, but how can I can do it through DNA spectroscopy? Is there a way to do it without making a standard curve?

 

[xanthines]

If all you want is a yes/no answer as to whether or not DNA is present, then it is very easy to detect that DNA with the proper equipment. All you need is a spectrometer capable of measuring absorbance at 260 nm. Just measure the OD (absorbance) of water (or whatever your DNA is in, possibly TE buffer if not water) and subtract that from the OD of the DNA. Some machines do that automatically, usually indicated by a "blank" option. Anything above zero indicates DNA is present. The higher the number, the more DNA. If you want to get an actual concentration, you'll have to a little more but not much.

-X

Hey it's my first time doing research, and I am not too far in my studies. So please don't laugh if this is a silly question...I am isolating a plasmid from E.coli through microcentrifuging, etc. I need to check if the DNA is in the final tube. I know I can do so through electrphoresis, but how can I can do it through DNA spectroscopy? Is there a way to do it without making a standard curve?

 

[Doctor&Geek]

Really easy way:

Just mix up a tiny bit of Ethidium Bromide you use for your agarose gels with an aliquot of your DNA. Put under UV. Use water or TE as control. If it glows, it has DNA.

 

[lwong]

Thanks so much to both of yall!

 

[ImmunoANT]

ummmm.... while you're at it, don't forget to measure A260/A280, if lower than 1.8, that often means protein contamination (1.6 is usu good enough for me 😛 )

 

[Doctor&Geek]

Lower than 1.6 can also mean contamination with ethanol as well.