Salt problem in cosmid DNA extraction - how to remove excess salts (Dec/27/2005 )

I am isolating 32kb cosmid from bacterial culture , Its very difficult o have a sufficient amount of DNA for sub-cloning. please give me some tips . Secondly a large amount of salts is also precipitating each time . how to get rid of these salts?

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rinsing your DNA pellet with 70% ethanol will help to remove excess salts, but will not do anything to increase your yield

I am sorry about your other question, I have not worked with cosmids and dont' know how to help you...but if it were a plasmid prep, I would first check the copy #, and second I would scale up the culture prior to purification

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For sub-cloning, I reckon you should do "midi-prep" or "large-prep" from 100ml or more culture. In my experience with BAC, there is no other way.

I don't know the size of the cosmid but, try column purification or dialysis to de-salt. In my knowledge, Wizard DNA-clean up kit is available for DNA upto 50kb.

Good luck anyway.

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