Ames Express Kits

Similar to the Ames strains, the Ames Express^TM strains also carry specific mutations in the histidine biosynthesis pathway. As a result, the Ames Express^TM strains are histidine-dependent and will not survive in a histidine deficient nutrient.
The EBPI Ames Express^TM strains are unique to the Ames strain as these strains also express either human P450 1A2 or GST-theta enzymes internally which allows for the bio-activation of xenobiotic molecules into DNA reactive species in the absence of a S9 mix.  The ability to induce revertant mutation through bio-activation makes these Salmonella strains the ideal biomarker in assessing mutagenic properties in test samples.  As a result, exposure and incubation of the EBPI strains with a test sample followed by selection for the revertant mutants in a histidine deficient background allows researchers to assess the rate of revertant mutation which will reflect the level of mutagenicity of the test sample.

Benefits of the Ames Express^TM Strains

1. The system expresses recombinant human proteins rather than rat liver extract allowing better correlation to human health.
2. Sequestering of mutagens by lipid components from S9 lysate mix is no longer a concern
3. Short-lived reactive DNA mutagens have a increased chance of detection within this Ames test due to the internal P450 1A2, P450 1A1, P450 2E1 and GST T1-1bio-activation processes

P450 1A1 is a Phase 1 enzyme that performs many oxidative activation reactions on a wide range of polycyclic aromatic hydrocarbons (PAHs) found in combustion processes, cigarette smoke, industrial activity and natural resource development. Although it is capable of performing heteroatom hydroxylation reactions similar to the P450 1A2, hydroxylation and epoxidation reactions on conjugated aromatic systems make up the bulk of activation reactions performed by this enzyme.

P450 1A2 is a Phase 1 enzyme found primarily in the hepatic tissue and is responsible for metabolizing polyaromatic hydrocarbons (PAHs), aromatic amines and nitro aromatics. It performs a variety of chemical reactions on several different xenobiotic classes and is a key contributor to the mechanistic mutagenicity of well known carcinogens like benzo(a)pyrene (B[a]P), PhIP and 4-aminobiphenyl.

P450 2E1 is a Phase 1 enzymes that preforms important oxidation activation reactions on a number of haloalkanes and some PAHs, but is more importantly involved as the primary activator for a family of molecules called nitrosamines. Nitrosamines are important carcinogens formed from a variety of processes including the acid catalyzed combination of nitrite and amines as well as a byproduct from disinfection of drinking water sources by UV light.

GST T1-1 is a Phase 2 enzyme responsible for attaching glutathione conjugate molecules to reactive sites on a toxicant. GST acts primarily as a detoxification enzyme and the products are, by enlarge, excreted without incident. However, certain classes of compounds produce reactive metabolites upon conjugation with GST.  Haloalkanes, organic thiocyanates, nitrosoguanides vicinal dihaloalkanes and quinones all produce reactive GST metabolites that cause mutagenicity. These reactions are important mutagenic pathways for several prominent pollutants and can serve as biomarkers for the presence of polychlorinated alkanes and alkenes in waste water effluent and drinking water samples.