Chris Upton cupton at sol.uvic.ca
Tue Jan 25 12:05:44 EST 1994

In Article <1994Jan24.214509.12970 at nrcnet0.nrc.ca>, nash at nrcbsa.bio.nrc.ca
(John Nash) wrote:

>I was curious as to why I could only get 1 X 10e9 some days and 1 X
>10e10 on others with the same batch of cells.
>Then I wrote down my controls on a grid...  They went something like
>this (from memory).
>Host: DH5 alpha or DH5alpha F'  - it didn't matter which.
>pUC8    1 x 10e10
>pUC18   1 x 10e10
>pUC18 derivative (from a colleague) 1 x 10e10
>pUC118 1 x 10e9
>pT7/T3 alpha 19 (BRL's phagemid) 1 x 10e9
>Now look at that... a ss phage origin (fd or M13) drops the
>electroporation efficiency down a log.
>A colleague (the one who lent me the pUC18 deriv) was able to
>reproduce these results...
>[ Call it the "Nash effect" after me ;-) To the humour impaired: My
>tongue is planted firmly in my cheek! ]

>John Nash                           (nash at nrcbsa.bio.nrc.ca)
>Institute for Biological Sciences,  National Research Council of Canada,
>                 Yet another Aussie-in-exile ;-)
>      *** Disclaimer:  All opinions are mine, not NRC's! ***

Does that hold for other methods of transformation? A lot of times phagemids
get used for no good reason. Here's one NOT to use them!!

Chris Upton 
Biochemistry & Microbiology
University of Victoria
PO Box 3055, Victoria
BC, Canada   V8W 3P6


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