L4 - Mutational signatures

Question 1

AMES test: what is it, how does it work, and what are the positives?

Answer 1

Used to assess the potential carcinogenic effect of chemicals by using the bacterial strain Salmonella typhimurium

Mix a compound with homogenised rat liver (allows metabolites to be formed) and grow it on bacteria - by counting the amount of bacterial mutations, a mutagenic score is formed

• Quick and inexpensive
• High-throughput
• Uses well-established model organism
• Salmonella typhimurium,
• Simple to perform
• Reliable
• Non-animal

Question 1

AMES test: what are the drawbacks to the test?

Answer 1

Limited predictive power: indicate whether a chemical is mutagenic, it cannot predict toxicity or the specific types of mutations that may occur in humans.

May not detect all mutagens: The test only screens for mutagens that cause frameshift mutations.

May not detect all mutagens: Some chemicals that are mutagenic in higher organisms may not cause mutations in the bacteria

May give false positives: Some chemicals that are not mutagenic in higher organisms may cause mutations in the bacteria

May not detect all mutagens: anything toxic and kills bacteria is not assessed for mutagenicity