Colin--
One classical test for lysogeny is to super-infect the bacterial
host. In this instance the phage lambda derivative DE3 carries the
immunity region from bacteriophage 21. Therefore plating an
appropriate phage with lambda immunity should lead to plaques and
plating one with imm21 should not (you could also test the imm21
phage on a non-lysogen to verify that it is capable of forming
plaques). As for PCR, I suspect any sequence from the left arm of
lambda should work nicely. Likewise, DE3 contains an insert of T7
gene 1 (the RNA polymerase) and presumably this would also be trivial
to detect using your PCR idea.
--Marc
Marc D. Perry
Department of Molecular and Medical Genetics
Faculty of Medicine
University of Toronto
1 King's College Circle
Toronto, Ontario
CANADA M5S 1A8
Tel.: (416) 978-0117
FAX: (416) 978-6885
marc.perry at utoronto.ca
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