Posted 01 September 2010 - 11:23 PM
previous yield on Maxi using invitrogen kit is around 1mg now not even 300ug
Giga (invitrogen) gave around 10mg but now not even 1mg
what could be the reason?.
I used just home source vacuum, but for the last Giga prep I used vacuum controller, is that could be the reason?
also how to calculate the density on this grown cultures and how much it should be?
Any help is appreciated/
Posted 02 September 2010 - 12:05 AM
Posted 02 September 2010 - 03:16 AM
Were both the high-yield culture and the low-yield culture grown in the same media and under the same conditions?
Were the A260/A280 ratios pretty much the same for both cultures? Remember, the spectrophotometer measures anything that absorbs the wavelength used -- a dirty sample will read higher than a clean sample, without necessarily containing more plasmid DNA. Do equivalent amounts of the samples appear different on an EtBr-stained gel?
It would be useful to have culture ODs to compare, to see if it's a culture growth issue or a plasmid extraction issue...
Posted 02 September 2010 - 06:53 AM
What the OD600 at the time of harvesting?