Mutagenicity study of fried sausages in Salmonella, Drosophila and mammalian cells in vitro and in vivo

The basic extract of pan-fried sausages was studied for mutagenic potential in seven test systems. Mutagenic activity was high in the standard Ames assay in the Salmonella typhimurium strains TA1538 and TA98 in presence of S9 mix. In vivo, in the intrasanguine host-mediated assay with strain TA98 on Aroclor-pretreated mice, the mutagenic activity of the extract was low. A borderline activity was seen in the SCE assay in vitro with V79 Chinese hamster cells in presence of S9 mix. No significant mutagenic action was found in the gene-mutation assay for thioguanine resistance with V79 cells, the Drosophila sex-linked recessive lethal test, the micronucleus test and the mammalian spot test.     

Mutagenicity of benzidine and benzidine-congener dyes and selected monoazo dyes in a modified Salmonella assay

We have evaluated the mutagenic activity of a series of diazo compounds derived from benzidine and its congeners o-tolidine, o-dianisidine and 3,3'-dichlorobenzidine as well as several monoazo compounds. The test system used was a modification of the standard Ames Salmonella assay in which FMN, hamster liver S9 and a preincubation step are used to facilitate azo reduction and detection of the resulting mutagenic aromatic amines. All of the benzidine and o-tolidine dyes tested were clearly mutagenic. The o-dianisidine dyes except for Direct Blue 218 were also mutagenic. Direct Blue 218 is a copper complex of the mutagenic o-dianisidine dye Direct Blue 15. Pigment Yellow 12, which is derived from 3,3'-dichlorobenzidine, could not be detected as mutagenic, presumably because of its lack of solubility in the test reaction mixture. Of the monoazo dyes tested, methyl orange was clearly mutagenic, while C.I. Acid Red 26 and Acid Dye (C.I. 16155; often referred to as Ponceau 3R) had marginal to weak mutagenic activity. Several commercial dye samples had greater mutagenic activity with the modified test protocol than did equimolar quantities of their mutagenic aromatic amine reduction products. Investigation of this phenomenon for Direct Black 38 and trypan blue showed that it was due to the presence of mutagenic impurities in these samples. The modified method used appears to be suitable for testing the mutagenicity of azo dyes, and it may also be useful for monitoring the presence of mutagenic or potentially carcinogenic impurities in otherwise nonmutagenic azo dyes.     

Mutagenicity of methyl isocyanate in the modified test conditions of Ames Salmonella/microsome liquid-preincubation procedure

Methyl isocyanate (MIC) was tested for mutagenicity using the Ames Salmonella/microsome liquid-preincubation procedure with slight modification of test conditions. In the modification the preincubation mixture was incubated at 10 degrees C for 60 min. MIC was assayed both in the presence and absence of Aroclor-1254-induced S9, using 5 tester strains of Salmonella typhimurium, TA97a, TA98, TA100, TA102 and TA104. MIC induced mutagenic response in two base-pair substitution strains, TA100 and TA104, in the presence and absence of S9. However, mutagenic response in the presence of S9 was low as compared to that in the absence of S9. In the comparative mutagenic activity at 3 different preincubation test conditions (37 degrees C for 20 min, 20 degrees C for 40 min and 10 degrees C for 60 min), optimum mutagenic response was observed at 10 degrees C for the 60-min test condition. However, no mutagenic response was observed at 37 degrees C for the 20-min test condition.     

Study of the causes of direct-acting mutagenicity in coffee and tea using the Ara test in Salmonella typhimurium

The mutagenic activities of 6 of the chemicals identified in coffee solutions were assayed with the Salmonella Ara test, under experimental conditions optimized for coffee mutagenicity. Caffeine was the only non-mutagenic compound. Among the other 5 chemicals, hydrogen peroxide was the strongest mutagen and chlorogenic acid the weakest; methylglyoxal, glyoxal and caffeic acid exhibited intermediate mutagenicities. The minimal mutagenic doses of these components correlated negatively with their relative concentrations in coffee. It was concluded that chlorogenic acid, caffeic acid, glyoxal and methylglyoxal cannot contribute alone to the mutagenicity of coffee in the Ara test, since their minimal mutagenic concentrations were much higher than their respective levels in the coffee samples assayed. By contrast, 40-60% of the mutagenic activity in coffee and also in tea could be attributed to their H2O2 contents. Catalase abolished more than 95% of the mutagenic activity of coffee, as detected by the Ara test. A similar sensitivity to catalase has been reported by other authors in relation to the coffee mutagenicity identified by the Salmonella His test. Nevertheless, the results presented in this paper suggest that the Ara forward and the His reverse mutation tests are sensitive to the mutagenicity of different constituents in coffee solutions. We propose that the His test, sensitive at high coffee doses, mainly recognizes the mutagenicity of methylglyoxal, whilst the Ara test, sensitive at low coffee doses, mainly detects the mutagenic activity of hydrogen peroxide. The data reported also suggest that the direct-acting mutagenicity(ies) detected by the Ara test in tea solutions is (are) based on similar, if not identical, mechanisms.     

Mutagenicity test of dyes used in cosmetics with the Salmonella/mammalian-microsome test.

37 dyes including 3 anthraquinone, 22 azo; 5 xanthene, 5 fluorandiol, and 2 thioindigo dyes, were tested for mutagenic potential with the Salmonella/mammalian-microsome test. Two frame-shift histidine mutants (TA1537 and TA98) and two base-pair substituted histidine mutants (TA1535 and TA100) of Salmonella typhimurium were employed. Both the spot test and the plate-incorporation assay indicated that one azo dye, D&C Orange No. 17, was mutagenic with three of the bacterial test strains. The mutagenic response of D&C Orange No. 17 was depressed by the addition of the microsomal fractions from rat livers. Of the chemicals used to synthesize D&C Orange No; 17 was depressed by the addition of the microsomal fractions from rat livers. Of the chemicals used to synthesize D&C Orange No. 17, beta-naphthol was not mutagenic but 2,4-dinitroaniline was mutagenic to the same Salmonella strains as D&C Orange No. 17 . Dimethyl sulfoxide extracts of lipsticks of similar formula but without D&C Orange No. 17 were tested in the plate incorporation assay. Only those containing D&C Orange No. 17 were mutagenic and the dye was mutagenic at concentrations consumed in normal daily use.     

The mutagenic action of nitroimidazoles. IV. A comparison of the mutagenic action of several nitroimidazoles and some imidazoles.

The mutagenic action of 51 imidazoles was investigated. The fluctuation test of Luria and Delbrück was used, with Klebsiella pneumoniae as test organism. 8 compounds, including 5 with a weak mutagenic action in the fluctuation test, were also investigated by the Ames test in which Salmonella typhimurium TA100 was used. Of the 51 imidazoles examined, 33 were nitroimidazoles. 31 of the latter appeared to be mutagenic, whereas out of the 18 other imidazoles without a nitro group only 2 were mutagenic. Several of the substances tested for mutagenicity showed an antimicrobial activity. No direct relationship between antimicrobial action, growth inhibition and mutagenicity was established. With methyl-nitroimidazoles a relationship was found between the chemical structure and mutagenic action. However, when the nitroimidazoles had a more complex chemical structure, a relationship between this structure and mutagenicity could not be established.     

Genotoxic activity of 1,3-butadiene and nitrogen dioxide and their photochemical reaction products in Drosophila and in the mouse bone marrow micronucleus assay.

The genotoxic activity of a photochemical reaction mixture of 1,3-butadiene and nitrogen dioxide was investigated in vivo in the mouse bone marrow micronucleus assay and the somatic mutation and recombination test in Drosophila (the wing spot test). Butadiene alone was not mutagenic in Drosophila, but induced micronuclei in mice at 10 ppm after 23 h of exposure. Nitrogen dioxide was not genotoxic in either test system. The photochemical reaction products were toxic but probably not mutagenic in Drosophila and not genotoxic in mouse bone marrow. The in vivo results do not confirm earlier in vitro results that demonstrated a strong direct-acting mutagenic activity of the photochemical products in Salmonella.     

Mutagenic activity of nine N,N-disubstituted hydrazines in the Salmonella/mammalian microsome assay.

The mutagenic activity of N,N-dimethyl-, N,N-diethyl-, N,N-dibutyl-, N,N-diisobutyl-, N,N-di(p-tolyl)-, N-ethyl-N-phenyl-, N,N-dibenzyl-, N,N-diphenyl- and N,N-diisopropylhydrazine was examined in the Salmonella/mammalian microsome assay using the strains TA1535, TA1537, TA97, TA98, TA100, TA102 and TA1530. All nine hydrazines were mutagenic in at least one tester strain, although of borderline significance for some of the compounds. The mutagenic potencies of the hydrazines varied 2-3 orders of magnitude, from very weak to moderate mutagenic activity. In general, the addition of S9 resulted in a lowering of the mutagenic activity and a lowering of the toxic properties of the hydrazines. The test results were relatively difficult to evaluate due to toxic effects of many of the test compounds on the test bacteria which may have resulted in an underestimation of the mutagenic potencies of some of the compounds. The pattern of mutagenic activity of the hydrazines in the different tester strains indicates that more than one mechanism of action may be involved in the mutagenicity.     

Microbiological mutagenicity studies of pesticides in vitro.

14 pesticides were tested as pure compounds for the induction of point mutations in four strains of Salmonella typhimurium--TA1535, TA1536, TA1537 and TA1538--in the presence and in the absence of rat-liver microsomal fractions and for the induction of resistance to low concentrations of streptomycin in the filamentous bacterium, Streptomyces coelicolor. The technique used was essentially the so-called "spot test". The pesticides investigated were: aminotriazole, Benomyl, Captafol, Captan, Dichlorvos, Dalapon-Na, Dinobuton, Dodine, Ioxynil, Mecoprop, Neburon, Picloram, Triallate and Trichlorphon. In Salmonella, Captan and Triallate were mutagenic on the TA1535 strain; Dichlorvos and Trichlorphon were negative in the spot test but mutagenic after incubation in liquid cultures of strain TA1535. By using the S. coelicolor forward-mutation test, aminotriazole, Dichlorvos, Picloram, Trichlorphon and Triallate were mutagenic with the "spot test" technique; Captan showed a weak mutagenic activity with a "plate-incorporated" technique.     

Mutagenicity tests of diflubenzuron in the micronucleus test in mice, the L5178Y mouse lymphoma forward mutation assay, and the Ames Salmonella reverse mutation test.

Diflubenzuron, one of a new class of pesticides believed to act via inhibition of chitin synthesis in the developing insect cuticle, was tested for possible mutagenic activity using the micronucleus test in mice, the L5178Y mouse lymphoma forward mutation test at the thymidine kinase locus, and the Ames Salmonella/microsome reverse mutation test. No mutagenic effect was found.     

Microbial mutagenicity of 3- and 4-ring polycyclic aromatic sulfur heterocycles

The stable isomers of 3- and 4-ring polycyclic aromatic sulfur heterocycles were tested for mutagenicity in the Ames standard plate incorporation test and a liquid pre-incubation modification of the Ames test. Of the 4 three-ring compounds tested, only naphtho[1,2-b]thiophene was mutagenic. Of the four-ring compounds, 7 of 13 were mutagenic in the standard Ames or pre-incubation Ames test. The highest activity for the 4-ring compounds was observed for phenanthrol[3,4-b]thiophene, a compound of approximately the same mutagenic potency in the Ames test as benzo[a]pyrene. The other active 4-ring compounds were of considerable less mutagenic potency than phenanthrol[3,4-b]thiophene. Mutagenicity for two of the 4-ring aromatic thiophenes could only be detected in the liquid pre-incubation Ames test. Salmonella typhimurium TA100 was the most sensitive strain to mutagenesis by these compounds, followed by TA98. All mutagenesis was indirect, requiring metabolic activation.     

Ames test: mutagenic activity of airborne particles collected on airconditioner filters during the fire at a Sandoz storehouse in Schweizerhalle on November 1, 1986

The mutagenic activity of methanol extracts from airconditioner filters was tested using the standard plate-incorporation procedure for the Ames test and the strains Salmonella typhimurium TA97, TA98 and TA100 as test organisms. In a first set of experiments filters from 4 buildings were investigated. For each building the mutagenic activity of a filter which was in use during the fire (fire-exposed) was compared with the mutagenic activity of a filter which was exposed for a similar time span to normal urban air (non-exposed). While for 1 pair of filters the non-exposed extract was more mutagenic than the fire-exposed material, the opposite was found for 2 other filter pairs, and in 1 case there was hardly any difference in the mutagenic activities of the fire-exposed and the non-exposed filter extracts. Overall differences by factors up to 100 were observed in the mutants/m3 air values of the most and the least mutagenic filter extracts. The second group of experiments was performed to investigate the variations in mutagenic activity of filter extracts occurring due to changes in the weather conditions. Airborne particles were collected for 3 consecutive periods of 10-11 days at the 2 buildings where the extracts of the fire-exposed filters had been found to be more mutagenic than the corresponding control materials. The differences between the strongest and the weakest mutagenic filter extracts of these series were similar to the differences observed previously between the fire-exposed filters and the non-exposed filter materials. The highest mutagenic activities found in the second group of experiments was similar, at both sites, to the mutagenic activities measured in the fire-exposed extracts from these 2 buildings. Since the differences in the mutagenic activities of filters exposed to urban air during the different meteorological conditions were similar to the differences observed between fire-exposed and non-exposed materials, it is not possible to state whether the fire led to the distribution of mutagenic chemicals, although it is theoretically possible. However, based on the observation that the maximal mutagenic activities of the fire-exposed and the non-exposed extracts were similar, the present study allows the conclusion that the mutagenic burden for the population of the area of Basel was not significantly increased by the fire in Schweizerhalle on November 1, 1986.     

Bio-antimutagenic effect of L-cysteine on diiodohydroxyquinoline-induced micronuclei in Swiss mice

The mutagenic potential of diiodohydroxyquinoline (DIHQ), a common anti-amebic drug, was tested using the in vivo micronucleus test in Swiss mice following oral administration. It was found to be mutagenic in a dose-dependent manner. Using the same model system, the bio-antimutagenic effect of the sulfhydryl compound L-cysteine against DIHQ was established.     

Absence of mutagenic activity of WHR-1142A, lidamidine hydrochloride, in 4 short-term tests for mutagenic/carcinogenic potential

WHR-1142A, lidamidine hydrochloride, an antidiarrhoeal agent, was tested for possible mutagenic/carcinogenic activity in the Ames Salmonella typhimurium/metabolic activation test, the micronucleus test, by analysis of metaphase chromosomes obtained from human lymphocytes grown in culture and in a cell transformation assay. No evidence of mutagenic/carcinogenic activity due to WHR-1142A, lidamidine hydrochloride, was found in any of the 4 tests.     

Comparison of the mutagenic activity of 5-hydroxymethyldeoxyuridine with 5-substituted 2'-deoxyuridine analogs in the Ames Salmonella/microsome test

4 antiviral drugs 5-hydroxymethyldeoxyuridine (HMUdR), 5-trifluorothymidine (F3TdR), 5-methoxymethyldeoxyuridine (MMUdR) and 5-ethyldeoxyuridine (EtUdR) have been evaluated for mutagenic activity in the Ames Salmonella/microsome test. The antimetabolites F3TdR and HMUdR were mutagenic in a dose-dependent manner in strain TA100. F3TdR also was mutagenic in strain TA1535. Rat-liver post-mitochondrial supernatant (S9) was not required for mutagenicity.     

Genotoxicity of carcinogenic N-nitrosopropylamine derivatives in the hepatocyte primary culture/DNA-repair test

The genotoxicity of N-nitrosodipropylamine, 8 of its oxidized derivatives and N-nitroso-2,6-dimethylmorpholine was examined in the hepatocyte primary culture (HPC)/DNA repair test. Nine N-nitrosamines which are known to be carcinogenic and mutagenic were clearly positive in the HPC/DNA-repair test. N-Nitroso(2,3-dihydroxypropyl) (2-hydroxypropyl)amine did not elicit DNA repair, but showed a borderline mutagenic response in the Salmonella/microsome test. Thus, the HPC/DNA-repair test displays a comparable capacity to the bacterial mutagenesis test for detecting the genotoxic effects of this class of carcinogens.     

Response of the L-arabinose forward mutation assay of Salmonella typhimurium to frameshift-type mutagens

The present study was designed to evaluate the capacity of the L-arabinose resistance test of Salmonella typhimurium in the detection of frameshift-type mutagens. To this end the response of the Ara test was examined with respect to 15 chemicals which had been previously described as able to revert the Ames tester strain TA97. The mutagenicity of each compound was determined by the liquid test under experimental conditions which optimize the mutagenic response of the Ara test with the tester strain BA9. Strain TA97 was used simultaneously with BA9. The Ara forward-mutation assay efficiently detected the mutagenic activity of 14 out of the 15 chemicals assayed. PR toxin was the only compound which gave a weak dose response without doubling the spontaneous mutant level. In comparison with the Ara test, a total of 3 chemicals (HZ, PE and PR toxin) were not found to be mutagenic with strain TA97. In most cases (11/15) the mutagenic response of the Ara test was comparatively greater than that of strain TA97. Three chemicals (DEO, PRF and 9-AA) were detected with quite similar degrees of sensitivity by both mutation assays. ICR-191, which seems highly specific in reverting frameshift mutations with added cytosines in a run of cytosines, was the only chemical with a lower mutagenic activity in the Ara test than in strain TA97. The results enhance the interest of the L-arabinose forward-mutation assay as an alternative to the set of specific tester strains used by the histidine reverse-mutation assay in massive, general and primary screening for genotoxic agents.     

The lack of mutagenic properties of patulin and patulin adducts formed with cysteine in Salmonella test systems.

The mutagenic properties of patulin and the patulin adducts formed with cysteine were tested with histidine auxotroph Salmonella typhimurium strains as indicator organisms. The tests were performed by microsomal activation and host-mediated assay. Neither patulin nor patulin--cysteine reaction mixture was mutagenic in these test systems.     

The DNA of recombinant plasmids acquires mutagenic activity in a Bacillus subtilis culture after the insertion of the human genome Alu repeat

In our previous work the mutagenic activity of recombinant plasmids (pBR322 carrying the human Alu repeat alone or in combination with preproinsulin or apo AI gene) in competent Bacillus subtilis culture was demonstrated. In present work it was shown that among seven tested plasmids only three revealed mutagenic activity (pBR322 and two Alu repeat-containing constructions). It seems that mutagenic activity is not inherent to any recombinant molecule in applied test system but depends on its structure. For example, Alu repeat of human genome may attach mutagenic properties to plasmids which either had no such properties, or lost them after gene engineering manipulations.     

Genotoxic effects of some organophosphorous pesticides. I. Induction of micronuclei in bone marrow cells in rat

The genotoxic effects of 4 organophosphorous pesticides, i.e. ekatin, fenitrothion, methylparathion and phorate, were examined employing the micronucleus test in bone marrow cells of the rat. Methylparathion and phorate were found to be mutagenic, while ekatin was weakly mutagenic. The frequency of micronuclei induction by fenitrothion did not differ significantly from that noticed in negative control.