A modified suspension test for estimating the mutagenicity of samples containing free and (or) protein-bound histidine.
The Ames test has not been very effective in estimating the mutagenicity of histidine-containing samples because external free and (or) protein-bound histidine in these samples would allow the histidine auxotrophs in such test samples to grow more compared with the negative controls that were used as the reference. This could give rise to a false positive.n this study, a modified suspension mutagenicity assay (MS assay) was developed. The tester strains were incubated in Luria-Bertani (LB) broth containing different concentrations of traditional Chinese medicines (TCMs) until the declining phase, and the test samples were assayed to be mutagenic or not by observing whether statistically significant differences were demonstrated in the relative reversion frequencies (RRFs) between the negative control groups and the test groups. Collectively, using LB broth as the test medium and comparing the RRFs in the declining phase made this assay less influenced by the presence of histidine in the test samples.The mutagenicity of some TCMs was measured with the MS assay. The results in MS assay were consistent with those in the mammalian bone marrow chromosomal aberration test, which indicated that the MS assay was appropriate to estimate the mutagenicity of samples containing free and (or) protein-bound histidine.
Liu
Bo
B
State Key Laboratory of Microbial Technology, Shandong University, Jinan-250100, People's Republic of China.
Jin
Jianling
J
Cheng
Yanfei
Y
Zhang
Huaiqiang
H
Gao
Peiji
P
D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects; D002478:Cells, Cultured; D002869:Chromosome Aberrations / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000633:toxicity*; D006639:Histidine / Q000378:metabolism*; D008297:Male; D051379:Mice; D009152:Mutagenicity Tests / Q000379:methods*; D009153:Mutagens / Q000633:toxicity*; D012486:Salmonella typhimurium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
D004365:Drugs, Chinese Herbal; D009153:Mutagens; D006639:Histidine