Virtualab Protocols (Chang Bioscience)
S. typhimurium Strain
Salmonella strains TA97, TA98, TA100, TA102, TA104, TA1535 and TA1537
are histidine auxotrophs. Both frameshift (e.g., TA98, TA1537) and
base-pair substitution (e.g., TA102, TA100, TA1535) are
presented. Additional markers (e.g, uvrB, rfa, pKM101 R factor plasmid) make the test more sensitive to
certain types of mutagens.
Revertants are identified as colonies that grow in the presence of low levels
if histidine.
Protocol
1. Grow Salmonella culture in 2.5% Oxoid Nutrient Broth #2 at
37 °C overnight with shaking.
2. Mix 5 ml test chemical, 50-100 ml
Salmonella culture and 50 ml 10% S9 (Aroclor 1254-induced
rat liver S9).
3. Incubate at 37 °C for 20 minutes without shaking.
4. Add 2.0 ml of molten top agar (0.8% agar, 0.5% NaCl supplemented with histidine and biotin)
and pour onto the Vogel-Bonner plates ( 1.5% agar, 2.0% glucose in Vogel-Bonner medium E (40 mM MgSO4,
520 mM citric acid, 2.87 M K2HPO4,
0.87 M NaHNH4 and autoclaved)).
5. Incubate at 37 °C for 2 days.
6. Score for positive colonies.
Order
Salmonella tester strains
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