Do we have a T1 problem?

Jan 11 2011 Published by under Uncategorized

No I’m not talking about internet connectivity, I’m talking about T1 bacteriophage. If you do any work with E. coli you may at some point time have an issue with this nasty little bastard when things stop working according to plan. Usually what happens is you are doing protein production work in E. coli and everything is going honky dory and you induce your production culture and nothing happens. You are left scratching your head wondering what the hell happened. Did I not induce properly? Did someone mess with the incubator shaker? Am I failure? Should I just go back to making methamphetamines in my parent’s basement?

You will ponder many of these questions but hopefully not too long before you work out that it might just be a contamination issue. Which could be caused a fair number of times by T1 phage. The easy trick to determining if T1 contamination is the root cause of your problems is to check you strain and determine if its positive for FhuA (Ferric Heme Uptake) or TonA, which is a receptor necessary for T1 uptake (Wagner).

Remember if you are using tonA+ E. coli and you don’t need the TonA which is non-essential by the way, then just switch to another strain like BL21; which you may need in the case of rare codons but that’s a whole other can of worms to opened somewhere and sometime else.

But if you need TonA, then you need to check by plating a lawn of the sensitive TonA-positive bacteria and leaving it uncovered in the suspected contamination area (your incubator shaker, workbench, etc.) for one hour and then incubate overnight. If you have contamination, you will see anywhere from a nickel to half-dollar sized plaques on the plate. Guess what, you’re fucked.

T1 is not easy to get rid off. The best solution of all is to not use T1-sensitive strains. You’ll need to bleach the hell out of everything as well as UV irradiate if possible. And I mean everything, water baths, glassware, specs, pipets, your wife and kids (the latter is probably deserving of a good bleaching anyways). This is serious business T1 can exist in aerosol form for up to a few months, so it’s going to take regular cleaning and testing intervals. In a previous lab it took about six months to a year of solid effort to eradicate our T1 infection.

New PI’s take heed of this if you are doing bacterial work and moving into the lab space of someone who used to do a lot of work with phages. I know when you think phages a lot of think old dead white guys who used to do replication and mutation work back in the 40’s and 50’s but some of us still use them to this day. Just be cognizant of it.

Wagner EF et al. 1979. Development of Escherichia coli virus T1: escape from host restriction. J Virol 29: 1229-31

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