In order to help you, more info. is needed. How long did you expose
the bugs? How did you plate the bugs- did you plate a lawn, followed by UV
treatment? When you say, "two of the twelve E. coli grew, do you mean two of
tweleve different strains at one fixed UV exposure time, or twelve different
times on the same strain? Certainly, E. coli with defects in the uvr
(Ultraviolet repair) system will make them more sensitive to UV exposure.
Also, whether the bugs you plate are in lag or log or stat phase will make a
BIG difference!! (Bugs in log phase are most sensitive). Finally, keep in
mind that UV has poor penetrability, so the heavy the lawn you plate, the more
survivors you will get; UV does not penetrate through plastic or glass, so I'm
not sure how you will conduct the experiment in broth grown cells in a test
tube. Perhaps others could help???!!!
Good luck.
David J. Mcgee
MCGEED at hal.hahnemann.edu
McPHU (Medical College of Pennsylvania and Hahnemann University)
Center City Campus
15th and Vine Streets
Dept. Microbiology and Immunology M.S. 410
New College Building 10302
Philadelphia, PA 19102
Phone: 215-762-8275
Fax: 215-762-1004
