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S. aureus plasmids - S. aureus plasmids (Oct/03/2005 )


I'm looking for some advices how to estimate how many plasmids (not a copy of one plasmid, but a number of plasmids which differ in size) are in a cell of Staphylococcus aureus.

thanks for answer


Dear Jarod,

I think what you can do is, do a plasmid extraction, run on gel, you should see several bands. They could be the same plasmid in multimeric form of could be different plasmid.

Excise those band out, gel purified, digest with 6 rare cutter RE. Run a gel and compare the RE cut plasmid with uncut plasmid. If the RE only cut once, your plasmid will be linearlised and it show a band different from circular plasmid. If RE not cut, you will see the band same size with your control. (Chose another rare cutter)

After you lenearlised all the band, you can compare how many different sizes band that you produced and that will show you how many different plasmid that S. aureus contain.

I did these once sometime ago, but a lot of try and error work. I wonder is there any bater way of doing.
Looking forward for input.

Best regards