Describe how the Ames test screens for potential environmental mutagens.Why is it thought that a compound that tests positively in the Ames test may also be carcinogenic?

Answer: The Ames test is a bacterial reverse mutation assay developed by Bruce Ames in the 1970s to detect potential mutagens. It uses a strain of Salmonella typhimurium, which has a mutation that prevents it from synthesizing histidine. When mixed with a potential mutagen and plated on a medium lacking histidine, the bacterium will grow if the mutagen induces mutations that reverse its histidine synthesis deficiency. A positive result in the Ames test indicates that the tested compound is a mutagen, which may also be carcinogenic because both processes involve DNA alteration. Although not definitive, the Ames test serves as a crucial screening tool for further investigation into a compound's carcinogenic potential.