Ghost band (was Re: How to get a single stranded DNA as long as
Jose de las Heras
(by josenet from tiscali.co.uk)
Tue Jun 12 16:31:50 EST 2007
"peter" <peter.ianakiev from gmail.com> wrote in message
news:1181593924.822581.168770 from q75g2000hsh.googlegroups.com...
> On Jun 11, 4:22 pm, Nick Theodorakis <nick_theodora... from hotmail.com>
>> ChenHA wrote:
>> > Perhaps I misremember, was it XL1 blue cells that produces the ghost
>> > band of ssDNA instead?
>> I seem to remember a discussion about NaOH irreversibly altering the
>> plasmid conformation to generate a ghost band during alkaline preps, but
>> perhaps there is more than one kind of ghost band.
>> Nick Theodorakis
>> nick_theodora... from hotmail.com
>> contact form:http://theodorakis.net/contact.html
> Guys keep it focussed ... the original poster asked a specific
> question - 2-3 kb ssDNA out of a plasmid with 3 kb insert. There is no
> such thing like "ghost" bands. If the culture is overgrown the plasmid
> does not have time to separate and you have occasionally concatenates
> - thats all.
actually, "ghost" bands do exist.
They do seem to be related to a change in conformation of the plasmid DNA
under alkaline conditions.
I remember vaguely an old paper, from the 70s, describing what conformation
circular DNA can take, and it was defined as "type V" DNA, or something like
I might be able to fish it out...
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