aspiration of 70% ethanol - DNA extraction protocol (Aug/02/2007 )
PLZ.......................i want to know the perfect steps in doing washing of DNA pellet with 70% ethanol and then how to aspirate it???????...........................and how much 70% eth. should i add to the pellet????????????
Best Regards
How about 2 or 3 drops from a plastic dropper.
typically I just use my gilson pipette to remove the 70% ethanol. The pellet can get deteched from the walls when soaking in 70% ethanol.
typically I just use my gilson pipette to remove the 70% ethanol. The pellet can get deteched from the walls when soaking in 70% ethanol.
Thank u very much
but
sorry, i need more detil expanition
pipett carefully the ethanol.then do a short spin and pipett the remaining carefully.
For etOH precipitation, add 1/10 vol of NaAcetate, mix and add at least 2.5volumes of EtOH100%
for washes well depends of the pellet' size, but for minipreps, i add 1ml, for midi prep, 1-3 ml.
For RNA, well i don't have big pellets so i wash with 1ml.
For etOH precipitation, add 1/10 vol of NaAcetate, mix and add at least 2.5volumes of EtOH100%
SORRY
what does that mean?????
ok just forget this step....
but are you currently working in a lab? this seems to me a very common technique....
to explain : Na acetate acidifies the solution and bring salts helping DNA pellet formation.
etoh makes the solution hydrophibic. DNA becomes insoluble and pellet...
Now i can understand u. best regards.
but i am using a kit for extraction of DNA. and there is no indication for using of sod. actate.
this is a typical situation that "drives me through the wall".
You sem to be a student so you must have supervisor in your lab who is here to explain and show you how to do this... 
i'm not angry to you but to your so called supervisor !!!...
Sounds very much like a case of neglect.
Jehane, I think you should spend some quality time reading up protocols and the reasons behind them. Find a book on molecular biology, protocols. These books can give a step by step protocol and importantly tell you why you are doing what you are doing.
Molecular Biology by Sambrook... is a good start.
Lastly, once you have added 1:10 volume 3M Sodium acetate and 3 volume of 100% ethanol, you do need to centrifuge your solution, to pellet down the DNA. Centrifuge for about 10min at 13000rpm (revolutions per minute)