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Updated: Oct 19, 2026
The Lambda Select cII Mutation Detection System
Published on: April 26, 2018
Establishment of a Salmonella tester strain highly sensitive to mutagenic heterocylic amines
T Kamataki1, A Suzuki, H Kushida
1Division of Pharmacobio-dynamics, Graduate school of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan. kamataki@pharm.hokudai.ac.jp
Abstract:
A co-expression plasmid (p1A2OR) carrying human CYP1A2 and NADPH-P450 reductase cDNAs and an expression plasmid (pOAT) carrying Salmonella TA1538/ARO cells. The CYP and OAT expressed in the Salmonella cells showed catalytic activity. The TA1538/ARO strain exhibited high sensitivity to heterocyclic amines (HCAs) such as 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,8-dimenthylimidazo[4,5-f]quinoline (MeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) as compared with the parent Ames tester strain TA1538. It is suggested that the intracellular expression of drug-metabolising enzymes makes the Salmonella cells highly sensitive to the HCAs.
Insights
Genetically modified Salmonella cells expressing drug-metabolizing enzymes show increased sensitivity to heterocyclic amines (HCAs). This enhanced sensitivity in Salmonella TA1538/ARO cells offers a novel tool for HCA detection and research.
Area of Science:
- Biotechnology
- Molecular Biology
- Microbiology
Background:
- Heterocyclic amines (HCAs) are mutagenic compounds found in cooked foods.
- Assessing HCA toxicity often involves bacterial mutagenicity assays.
- Drug-metabolizing enzymes play a crucial role in HCA activation and detoxification.
Purpose of the Study:
- To develop a Salmonella strain with enhanced sensitivity to HCAs.
- To investigate the role of intracellularly expressed drug-metabolizing enzymes in HCA sensitivity.
- To create a novel tool for HCA detection and research.
Main Methods:
- Co-expression of human CYP1A2 and NADPH-P450 reductase cDNAs in Salmonella.
- Construction of a Salmonella TA1538/ARO strain harboring these cDNAs.
- Evaluation of catalytic activity of expressed enzymes.
- Testing sensitivity to various HCAs (MeIQ, IQ, MeIQx, PhIP) compared to parent strain.
Main Results:
- Successful expression of active CYP1A2 and NADPH-P450 reductase in Salmonella.
- The engineered TA1538/ARO strain demonstrated significantly higher sensitivity to HCAs.
- The parent Ames tester strain TA1538 showed lower sensitivity to the tested HCAs.
Conclusions:
- Intracellular expression of drug-metabolizing enzymes enhances Salmonella sensitivity to HCAs.
- The engineered Salmonella strain serves as a sensitive reporter for HCA activity.
- This approach offers a valuable tool for studying HCA metabolism and mutagenicity.
