ABSTRACT
The Center for the Biology of Natural Systems was certainly an interesting place back in 1977, with a relatively small group of talented people working with Barry Commoner on exciting topics: energy, nitrate water pollution, appropriate technology for developing nations, scientific information, organic farming. Barry had convinced the Environmental Protection Agency of the potential usefulness of applying bacterial mutagenesis as a way of checking environmental contamination in water, air, and in connection with industrial production. Since the microsomes had been obtained from rats treated with Polychlorinated Biphenyls (PCBs), one hypothesis suggested that PCB might be involved in the increased mutation rate after the addition of microsomes. Barry and his co-workers had discovered that some components of one of the ingredients used for growing bacteria—beef extract—contained contaminants capable of increasing the bacterial mutation rate. Bruce Ames had the bright idea of incorporating in the assay a preparation obtained from rat liver, which could perform complicated chemical reactions on a bacterial plate.
