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Help Needed! DNA sample dispersed b4 electrophoresis - (Oct/09/2005 )

Hi,

I have extracted B. subtilis DNA using by alkaline lysis and precipitate using isopropanol and ethanol.

I even have completed dried the ethanol with heat-drying speedvac.

however, when I mix with gel loading buffer and load my sample into agarose gel well, the sample sank at the first place. But as soon as I remove my pipette from the gel, the trace of gel loading buffer with my sample started to dispersed into the buffer. It seemed like a thread unwind from top till the bottom of the well.

I thought my sample contained ethanol or some other contaminants that might cause all these. So, I freeze-dried my DNA sample again and I still face the same problem.

Was this due because my DNA sample was too viscous? The concentration of my DNA is very high.

Please help me!

Thanks!

-siaupigu-

QUOTE (siaupigu @ Oct 9 2005, 09:37 AM)
Was this due because my DNA sample was too viscous? The concentration of my DNA is very high.


That would be my first guess... Dilute it 1:10 or so, and try again?

What was the original culture volume, and what volume have you resuspended the resulting DNA in?

-HomeBrew-

Original volume of culture was 100mL with OD of around 2.5. The reference method that I have used suggested OD of around 1.0 only.

After speed vac, I resuspended into 4 tubes. Then I freeze-dried the four tubes again. I resuspended the four tubes, each around only 300 microL with tube 2 around 500 microL.

-siaupigu-