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Unidentified DNA bands - (Mar/12/2009 )

I have been testing some DNA extraction kits, to purify DNA from gram negative bacteria.

The latest one I have tried (Qiagen DNeasy) has given me a nice, clean DNA extract. However, when I ran the extract on an agarose gel, as well as having a nice clear band at the top (presumably the genomic DNA), I also got 2 bands that were aproximately 1600 and 900 bp in length.

The bacteria I used were Vibrio natriegens and E. coli. Having spoken to a colleague who has also done some DNA extractions with the same kit, for E. coli, she also got the same banding pattern.

Has anybody else seen this? And does anyone have any idea what the bands could be?

-D I Walker-

D I Walker on Mar 12 2009, 05:56 AM said:

I have been testing some DNA extraction kits, to purify DNA from gram negative bacteria.

The latest one I have tried (Qiagen DNeasy) has given me a nice, clean DNA extract. However, when I ran the extract on an agarose gel, as well as having a nice clear band at the top (presumably the genomic DNA), I also got 2 bands that were aproximately 1600 and 900 bp in length.

The bacteria I used were Vibrio natriegens and E. coli. Having spoken to a colleague who has also done some DNA extractions with the same kit, for E. coli, she also got the same banding pattern.

Has anybody else seen this? And does anyone have any idea what the bands could be?


Maybe a plasmid :lol:

-pesji-