Evaluation of the SOS/umu-test post-treatment assay for the detection of genotoxic activities of pure compounds and complex environmental mixtures.
This study presents an evaluation of the SOS/umu-test after introducing an additional dilution and incubation in the post-treatment assay. This treatment reduces the influence of coloured test compounds that otherwise affect the colorimetric determination of the beta-galactosidase activity and the bacterial growth measurement during the testing of complex environmental samples. The post-treatment assay significantly increased the beta-galactosidase activity and consequently the enzyme induction ratios at higher doses of model genotoxins 4-nitroquinoline-N-oxide, N-methyl-N'-nitro-N-nitrosoguanidine, 2-aminoanthracene, benzo(a)pyrene with low or no effect on the sensitivity of the test itself. On the other hand tests of environmental extracts indicated significant increases in sensitivity after additional incubation. 4-Nitroquinoline-N-oxide treatments of bacteria in the test affected cell division and caused filamentous growth. The size of filamentous bacteria and incidence rate of the length categories was positively correlated with the concentrations of genotoxins. Presence of filamentous tester bacteria proved induction of SOS response and genotoxic activity of environment samples in SOS/umu-test.
Hamer
B
B
Laboratory for Marine Molecular Toxicology, Center for Marine Research, Ruder Boskovic Institute, HR-52210 Rovinj, Croatia. hamer@cim.irb.hr
Bihari
N
N
Reifferscheid
G
G
Zahn
R K
RK
Müller
W E
WE
Batel
R
R
D015112:4-Nitroquinoline-1-oxide / Q000633:toxicity; D000873:Anthracenes / Q000633:toxicity; D001426:Bacterial Proteins / Q000235:genetics*; D001564:Benzo(a)pyrene / Q000633:toxicity; D002455:Cell Division / Q000187:drug effects; D004259:DNA-Directed DNA Polymerase; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000633:toxicity*; D029968:Escherichia coli Proteins; D008769:Methylnitronitrosoguanidine / Q000633:toxicity; D009152:Mutagenicity Tests / Q000379:methods* / Q000592:standards; D009153:Mutagens / Q000633:toxicity; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D013014:SOS Response, Genetics / Q000235:genetics; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D001616:beta-Galactosidase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
D000873:Anthracenes; D001426:Bacterial Proteins; D004785:Environmental Pollutants; D029968:Escherichia coli Proteins; D009153:Mutagens; D011993:Recombinant Fusion Proteins; D008769:Methylnitronitrosoguanidine; D001564:Benzo(a)pyrene; D015112:4-Nitroquinoline-1-oxide; C006593:2-anthramine; C078202:UmuC protein, E coli; D004259:DNA-Directed DNA Polymerase; D001616:beta-Galactosidase