a. Transformation efficiency vs cell density

Greg Nattrass gnattras at waite.adelaide.edu.au
Fri May 2 20:19:24 EST 1997

Howdy all,

When preparing competent E. coli the cell density is monitored using
OD600nm. I generally grow DH5a between 0.5-0.6. I've been using a
protocol by Inoue, 1990 (Gene). How do you determine the final
resuspension volume. How many viable cells/ml should the competent cells
be resuspended at? 

Also, this method is supposed to produce competent cells returning 
10/9 (10 to the 9) transformants. They used pBR322 as their
transformation control while I've used pBluescript. Does the plasmid
vector used have any effect on the transformation efficiency?

Greg Nattrass
University of Adelaide

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