BRUCE N. AMESSenior Scientist Children’s Hospital Oakland Research Institute Oakland, California Professor Emeritus University of California, Berkeley© PAUL SIMCOCK PHOTOGRAPHYOn an otherwise ordinary day in 1964, Bruce Ames picked up a box of potato chips and read the list of ingredients. A biochemist at the National Institutes of Health (NIH) in Bethesda, Maryland, Ames spent his days studying mutations in strains of Salmonella, so it wasn’t unusual that he began to wonder if any of the preservatives or chemicals on that long list of ingredients might mutate DNA. Ames decided to use his Salmonella to try to detect genetic damage caused by chemicals. “I figured the world needed some quick, easy test to detect mutagens,” says Ames.
Ames had hundreds of strains of S. typhimurium with mutations in the genes required to produce histidine, a standard amino acid for making proteins. These strains could not grow without the addition of histidine. When millions of bacteria were placed in media lacking the amino acid, however, a few would spontaneously mutate, produce histidine again, and survive as a colony. Ames figured if he added a chemical, such as a potato-chip preservative, to the Salmonella strains, and the chemical increased the number of surviving colonies, it was a mutagen.
“Nutrition is a muddy field, but I like getting into muddy fields.”
Ames began tinkering with the test as a hobby. Then, in 1967, when he moved to the University of California, Berkeley, he got some ...
