well it depends but generally i ml should be sufficient to wash the DNA pellet. try to aspirate the ethanol carefully...add i ml of 70% ethanol again...centrifuge briefly and aspirate the total ethanol and then if possible go up to the dessicator for remaining ethanol if any. keep it for 30 mins or so... i hope this helps.
Thanks Nick. Very helpful.
I still want to know how much ethanol should be used for washing.
Tips on ethanol wash after nucleic acid precipitation
Posted 10 March 2009 - 10:52 AM
Posted 06 September 2009 - 08:23 AM
Posted 06 September 2009 - 05:09 PM
I just started working in a lab, but I've always been using 300 ul of 70% EtOH, followed by 300 ul of 99% EtOH after a miniprep and my supervisor said that's fine. But the preps are obviously dirty because they can't be cut with REs. So should I always wash with a minimum of 1 ml?
As a few others have stated, the actually volume isn't the most critical issue, so I wouldn't stress too much over it; you PI's advice is probably the one to follow.
Having said t hat, when we had digestion issues, we did one of two things. Once the DAN was resuspended, we put it through a second EtOH precipitation (or did a PCR cleanup on it). This is fine for most contaminants.
If, however, the repeat precipitation didn't do the trick, we went back and recultured, but we used LB. A few of our group found that overnight culturing with the really rich media gave higher yields of cells and plasmids (no surprise there!), but the DNA quality was lower. Growing cells in LB gave lower yields (fixed by larger cultures!) but better digestion.
Posted 07 September 2009 - 05:54 PM
Not sure, but I would imagine the answer is somewhere in the area of metabolite buildup, particularly with an overnight incubation. Possibly aeration may play a part.
Interesting! I'm using YT, which according to my sources (http://micro.fhw.oka...media/lbyt.html), is rouhgly the same as LB for a 1 L stock.
Any idea on why a less rich medium would give better digestion results?
Posted 30 July 2010 - 09:11 AM
Let me know if you want me to post the pdf somewhere.