Staff scientist, Chemotherapy-Fermentation Lab, NCI Frederick
The BIA was used to screen fermentation broths for DNA damaging
activity, as putative new cancer chemotherapeutic agents (Elespuru and
White, 1983) supported by the Natural Products Branch of the NCI. I used
243 mm x243 mm bioassay plates - petri dishes with a layer of top agar
containing BIA strain BR 513 - to spot 100 fermentation broths in a 10
by 10 grid. This might be considered one of the most boring, mundane lab
jobs imaginable. Fermentation broths yielding colored spots, with DNA
damaging agents present, were further characterized by chemists to
isolate the active principle in the broth and determine if it was a new,
undiscovered agent. There were usually many colored spots on the plate,
with characteristics indicating a rough dose-response in each spot (a
ring was a high dose with a toxic center).
One such spot was processed by the chemists and fraction samples
provided in order to follow the active principle. But I found nothing
active in any of the samples. The same result ensued with subsequent
samples. As our project was closed down, I had moved to a different lab
where these tests were performed. After a year had elapsed, it finally
occurred to me that the lighting conditions were different in the new
lab. Thus, I re-tested some samples under the yellow light conditions in
the new lab, as well as under ordinary white lights. Eureka! That
produced an all or nothing result with nothing under the yellow lights.
We had discovered a photoactive DNA damaging agent. It turned out to
have been discovered in multiple labs (with different names), but no one
knew it was activated by ambient lighting.