Circle Grow

[ROBERT BUTCHER]

In article <1997May29.111643.3846 at leeds.ac.uk> daniellh at biovax.leeds.ac.uk writes:
>From: daniellh at biovax.leeds.ac.uk
>Subject: Circle Grow
>Date: Thu, 29 May 1997 12:16:43 +0100 (BST)

>Hi, Circle grow was used in our lab a while ago instead of LB, and was
>apparently very good. However, there is no manufacturers name on the
>bottle, and we have no instructions! Has anyone used this (it comes
>in pellets), and could they let me know the manufacturers name and/or
>how many pellets in what volume of water is needed to be equivalent to
>LB media for growing DH5 alpaha e-coli.
>Thanks in advance for any info, Dani.
>e-mail direct to meddh at medphysics.leeds.ac.uk

Hi, we used CG a lot before (came as a powder then) returning to LB due to 
cost. Myself i was growing highcopy number plasmids (pKS and M13mp18 etc pUC 
derivatives) so cant comment upon low copy number plasmid propogations. 
However, with DH10a, DH5a and XL1-B hosts the growth rate is faster and the 
cell density attained at late log-stationary phase about 3 fold higher. The 
miniprep yields by various methods was about 4-5 fold higher than LB so the 
number of plasmid copies per cell probably didnt alter dramatically, just the 
number of cells per ml. However, remember this may not be the case for low 
copy number plasmids which may be improved more!
However, we found that (again for these high copy plasmids only, so i cant 
comment on low ones) if you enrich LB by doubling the yeast extract, adding 
50% more tryptone and similar peptone and reduce NaCl by 10%, you get a media 
that is nearly as good as CG but a fraction of the price except that 
rearrangments of some repetative insert sequences was enhanced slightly.
Good luck,
Rob