A new Salmonella tester strain expressing a hamster acetyltransferase shows high sensitivity for arylamines.
A hamster acetyltransferase, AT-I, has high activities for N-acetylation of arylamines, O-acetylation of N-hydroxyarylamines and N,O-acetyltransfer of N-hydroxyarylacetamides. In the present study, the cDNA was expressed in Salmonella typhimurium TA1538. The new SAT138 strain expressing high levels of AT-I showed remarkably high sensitivity (> 10,000 fold) for a carcinogenic intermediate, N-hydroxy-2-acetylaminofluorene, in an Ames mutagenesis test as compared to the parental TA1538 strain. SAT138 had 650-1,600-fold higher sensitivities for mutagenesis induced by 2-acetylaminofluorene and benzidine in the presence of S9 mix. Higher sensitivities (32-560-fold) were also observed with N-hydroxy-2-aminofluorene, N-hydroxy-4-aminobiphenyl, N-hydroxy-4-acetylaminobiphenyl, N-hydroxy-4-propionylaminobiphenyl and N-hydroxy-phenacetin in the absence of S9 mix. These high sensitivities to arylamines and the related chemicals are accounted for by the efficient expression of AT-I in the cytosol of this bacterium. The unique characteristics of SAT138 having high N-hydroxyarylacetamide N,O-transacetylating activity, which is defective in Salmonella acetyltransferase, provide broadened and high sensitivities for the detection of mutagenic N-substituted chemicals in the Salmonella mutagenesis test.
Ando
M
M
Toxicology Research Laboratory, Meiji Seika Kaisha, Ltd., Yokohama, Japan.
Shindo
Y
Y
Fujita
M
M
Ozawa
S
S
Yamazoe
Y
Y
Kato
R
R
D000123:Acetyltransferases / Q000235:genetics* / Q000378:metabolism; D000588:Amines / Q000633:toxicity*; D000818:Animals; D002384:Catalysis; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary; D009152:Mutagenicity Tests / Q000379:methods*; D010957:Plasmids; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism
D000588:Amines; D018076:DNA, Complementary; D000123:Acetyltransferases