10. the ames test in a nutrient medium that lacks histi dine, a thin layer of agar containing 10 salmonella ty- phimurium histidine auxotrophs (mutant cells tha

10. The Ames Test In a nutrient medium that lacks histi dine, a thin layer of agar Containing 10 Salmonella ty- phimurium histidine auxotrophs (mutant cells that require histidine to survive) produces ~13 colonies over a twO-day incubation period at 37 °C (see Fig. 25-19). How do these colonies arise in the absence of histidine? The experimernt is repeated in the presence of 0.4 ug of 2-aminoanthracene. The number of colonies produced over two days exceeds 10,000. What does this indicate about 2-aminoanthracene? What can you surmise about its carcinogenicity? lant oolle