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.