Questions about DNA recovery and cloning

Alexander N. Kukushkin kan at mmcd.cyt.ras.spb.ru
Wed Feb 26 13:40:19 EST 1997


>           Hello everybody, I have questions to ask for your help.
>   I have used GeneClean to recover DNA from agarose.  After eluting the DNA
>   in TE, I discover quite serious DNA degradation from gel electrophoresis.
>   I suspect the sources of contamination: TE or GlassMilk or both.  In order
>   to eliminate the problem, I autoclave the TE and the question is, is it
>   possible to autoclave the GlassMilk without affect the DNA-binding
>   activity?

I think the glassmilk can be quite autoclaved.

>           The second question is what density of the E.coli (OD600) suitable
>   to make competent cells?

Usually OD600 must be about 0.5.

>   Is it necessary that the higher OD (e.g. 6.0), the lower transformation
>   efficiency as a result?

Yes, of course.
Alex



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