phage attack

benedik at benedik at
Tue Oct 17 17:35:07 EST 1995

In article <thomas.7.307EC6ED at>
thomas at (Thomas Zander t3013) writes:

> From time to time our lab gets problems with phages, i.e. lysing cultures, 
> plaques etc. What assays could be performed (eg. spot-titering on top-agar, 
> but what strains should be used) to distinguish whether we are attacked by an 
> normal P1 or an entire-lab-strain-collection-killing T1? 
> Thanks  Thomas
> -

I would be surprised if it were either one. Phage P1 generally gives
absolutely miserable small plaques. So if you see nice plaques on
plates it probably isn't P1.  T1 is definately lab killing. But if I
remember correctly it makes enormous plaques on a plate (1cm size) and
if it were T1 then everything would be lysing by now, not
intermittently. T1 is incapable of infecting E. coli carrying ton
mutants (T-one resistant = ton). If you suspect P1 you could get a P1
lysogen and verify that your plaques won't grow. There are many other
phages out there.

I guess you could try spot titering on some different hosts and seeing
what you have.

alternately, if you always use a common strain, you could generate a
phage resistant derivative for your specific phage contaminating your

Michael Benedik               benedik at
Biochemical Sciences
University of Houston
Houston, TX 77204-5934

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