In an experiment employing the methods of the Ames test, two his- strains of Sal

Question

In an experiment employing the methods of the Ames test, two his- strains ofSalmonella are used. Strain A contains a base substitution mutation, and Strain B contains a frameshift mutation. Four plates are prepared to test the mutagenicity of the compound ethyl methanesulfonate (EMS). Plate 1 is a control plate with Strain A and S9 extract but no EMS. Plate 2 is also a control plate and contains Strain B and S9 extract but no EMS. Plate 3 contains Strain A along with S9 extract and EMS, and Plate 4 contains Strain B, S9 extract, and EMS.

a. Why is the S9 extract added to each of the plates?

b. Suppose the compound being tested was proflavin instead of EMS. Would this change the Ames test results? Explain why or why not.

Explanation / Answer

a. S9 rat liver extract is added to mimick conditions similar to that in the liver metabolism. which will hep assess the effects of the mutagen breakdown in mammaliam hepatic system.

b. proflavin is also known to be mutagenic. thus usage of proflavin instead of EMS would not produce different results.

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