No banding in CsCl Spin,Why?

Stephanie Yong spyong at
Mon Aug 12 06:12:26 EST 1996


I tried to purify my plasmid through CsCl centrifugation, and there was no
band.I used the Alkaline Lysis method using Solution 1,followed by Solution
2 and 3.Then I added 1g/1ml of CsCl into the lysate with Ethidium Bromide
and was set to spin in a 15ml ultracentrifuge tube.I used a  Sorvall
vertical rotor at 45,000rpm for 16hrs at 21 degree Celcius.

Should I precipitate after Solution 3,then resuspend in TE first before
adding CsCl?

I though my broth was contaminated and it wasn't my  E.Coli containing my
plasmid that was growing,but,I've double checked my plasmid through a
miniprep and it is there,no contamination.

Please advise.

My E-mail is : spyong at

Thank you,

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