Chlorampehical inhibit ssDNA packaging?

Dr. James E. Graham graham at
Sat Aug 3 19:31:37 EST 1996

It's a bit early, but it seems as if inclusion of chlormaphenical in the 
growth media at 50 ug/ml prevents some aspect of packaging single 
stranded plasmids with an M13 helper phage system.

I've just gotten through a few days of "no single-strands" and tired 
another packaging reaction with as slightly different media (no PO4 
buffer) and the same plasmid, and two different helper phages (VCSM13 or 
R408), leaving out the antibiotic selection for the plasmid. Bingo,
single -stranded plamsids.

This has not been a problem with ampicilling or spectinomycin in the 
past, where it tended to increase the relative yield of the desired 
product. I had heard rumors of the undesirability of using "drugs" in 
these reations before, and thought it might be the hang up here.

Anyone else seen it? Please E-mail a copy of your response.


J. Graham PhD 
Biology Department 
Washington University of St. Louis 
(Listowner, Amazons-l Digest)  

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