Streptomycin resistant E.coli via rpsL

Cliff Mintz mintz at CNJ.DIGEX.NET
Wed Jan 18 09:12:32 EST 1995

	Based on my experience, rpsL does not confer spectinomycin 
resistant to the strain that carry the mutation.  However, spectinomycin is 
difficult to work with on certain strains of E. coli.  I have also 
encountered low levels of Spr in these strains. Raising the 
concentration as you suggest should do the trick.
			Cliff Mintz
 On Tue, 17 Jan 1995, 
Duncan Clark wrote:

> Hi Folks,
> Does anyone know if an rpsL E.coli ie streptomycin resistant is 
> automatically spectinomycin resistant? I  have the Str/Sp gene 
> from Tn7 on a multicopy plasmid (one of the few antibiotic genes that 
> is stable on v.high copy vectors - the others being Amp and Kan) and 
> use spectinomycin 50ug/ml as my selection. Unfortunately I am finding 
> that my normal strains of choice for other applications are rpsL and 
> give a detectable background on spectinomycin plates. I will take the 
> concn up to 200ug/ml which I know the plasmid quite happily copes 
> with and see if that does the trick. However it would be nice to know 
> if rpsL is automatically Sp resistant.
> Thanks
> Duncan 
> -- 
> -----------------------------------------------------------------------------
> My mind's made up. Don't confuse me with the facts!

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