Photo of Bruce N. Ames

Bruce N. Ames

  • National Medal of Science
  • Biological Sciences

For changing the direction of basic and applied research on mutation, cancer and aging by devising a simple, inexpensive test for environmental and natural mutagens, by identifying causes and effects of oxidative DNA damage, and by translating these findings into intelligible public policy recommendations on diet and cancer risk for the American people.

Factors that can alter DNA (like UV rays and certain chemicals) are called mutagens; mutagens that lead specifically to cancer are known as carcinogens. Carcinogens can be found in some items we use everyday: food, cosmetics, and even medicine. In the past, we’ve used mutagen-detecting tests that were not only costly, but also time-consuming. Meaning, by the time scientists discovered what contained mutagens, those products were bought and used. Thanks to Bruce N. Ames and his test—called the Ames Test—detecting these chemicals is now efficient and cost effective.

Unlike animal models, the Ames Test uses a mutant strain of Salmonella Typhimurium, saving both time and money. This mutant strain is incapable of producing histidine, an amino acid it needs to survive. The test works by plating the bacteria with the substance being tested on agar containing enough histidine to allow for the bacteria to survive a short while. If the strain survives after using up the histidine on the plate, it is because the tested substance contains mutagens that change the bacterial DNA such that the strain produces its own histidine.

Because of this test, we’ve been able to reformulate products with cancer-causing ingredients for enjoyable and safe consumption!

Kristen Brida