Ames test

Definition

The Ames test is a biological assay used to assess the mutagenic potential of chemical compounds by observing their effect on the mutation rate of bacteria. It uses strains of Salmonella typhimurium that carry mutations in genes involved in histidine synthesis.

5 Must Know Facts For Your Next Test

1. The Ames test was developed by Bruce Ames in the 1970s.
2. It utilizes mutant strains of Salmonella typhimurium that cannot synthesize histidine, requiring it for growth unless a reverse mutation occurs.
3. A positive result indicates that the tested substance increases the mutation rate, suggesting it may be a potential carcinogen.
4. Rat liver extract is often added to mimic metabolic processes and detect pro-mutagens.
5. The test involves measuring the number of colonies formed on agar plates lacking histidine.

Review Questions

• What is the primary purpose of the Ames test?
• Why are mutant strains of Salmonella typhimurium used in the Ames test?
• How does rat liver extract contribute to the Ames test procedure?

Related terms

Mutagen:

An agent, such as radiation or a chemical substance, that causes genetic mutation.

Carcinogen:

A substance capable of causing cancer in living tissue.

Reverse Mutation: A genetic change that reverses the effect of a previous mutation, restoring the original phenotype.