E.coli cultures lysing after induction

Peter Ashton pda100 at york.ac.uk
Tue Aug 20 06:04:13 EST 1996

We have a strain of E.coli that we have been using for a few weeks now 
without any problems. Suddenly, the cultures we are growing have started 
lysing whenever they are induced with ITPG. The bulk of the lysis seem to 
occur within the first hour after induction.

No one here has come across anything like this before, so I was wondering 
if anyone out there has had similar problems. There are a few things that 
have changed between the successful and the failed cutures, which we are 
trying to unravel:

1. We are using new stocks of culture medium (M9)

2. We are using a different stock of IPTG (which is possibly older than
   the original stock)

3. We have move into a new lab.

We are checking the medium and the IPTG (using somebody else's stock that 
is definitely OK), and we don't think that moving labs should have had 
too drastic an effect. However, one suggestion that has been made is that 
we have managed to get some phage or other into our E.coli strain.

Does anyone know of a phage which would respond to IPTG like this? It 
seems very unlikely to me (surely someone else round here would have had 
the problem by now?), but I thought I would ask in case we are missing 
soemthing obvious...

Thanks in advance

Pete Ashton
pda100 at york.ac.uk

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