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The significance of mutagens in food
Mutation Research, 113 (1983) 221-327 Elsevier BiomedicalPress
221
European Environmental Mutagen Society Abstracts of papers presented at the 12th Annual Meeting of EEMS on Mutagens in our Environment, June 20th-24th, 1982, Dipoli, Espoo (Finland)
Adler, I.-D., Institute of Genetics, GSF, D-8042 Neuherberg (F.R.G.) Germ-cell sensitivity in mammals
A characteristic feature of chemical mutagens is their differential spermatogenic response to mutation induction (Ehling, Mutation Res., 26 (1974) 285). Dominant lethal mutations and, in many cases correspondingly, heritable translocation induction follows a particular sensitivity pattern for various chemicals in post-spermatogonial germ cells (Generos 0 et al., Mutation Res., 76 (1980) 191). Chemically induced gross chromosomal changes in spermatogonia are eliminated by germinal selection (Adler, in: Cytogenetic Assays of Environmental Mutagens, Allanheld, Osmun, 1982, p. 249). In contrast, gene mutations are transmitted from stem-cell spermatogonia through meiosis to the offspring. In the specific-locus test mitomycin C and ethylnitrosourea are most effective in spermatogonia and ineffective in post-spermatogonial stages (Ehling et al., Mutation Res., 92 (1982) 181). Cyclophosphamide and methyl methanesulfonate react in the opposite way (Russell, L.B. et al., Mutation Res., 86 (1981) 329). Procarbazine and triethylenemelamine are effective in both types of germ cells, however, with different mutation rates (Ehling, Arch. Toxicol., 46 (1980) 123). Differences in oocyte sensitivity have been observed with mitomycin C and procarbazine. The response to induction of specific-locus mutations in oocytes was lower than in spermatogonia (Ehling, in: Environmental Mutagens and Carcinogens, University of Tokyo Press, 1982, p. 709). These differences in mammalian germ-cell sensitivity are an important factor for the evaluation of genetic hazards due to human chemical exposure.
2 Aeschbacher, H.U., Nestl~ Research Department, CH-1814 La Tour-de Peilz (Switzerland)
0165-1161/83/0000-0000/$03.00 © 1983 ElsevierSciencePublishers
222
The significance of mutagens in food Recently numerous in vitro mutagenicity investigations have been carried out on foods. They have mainly focused on the effects of naturally occurring flavonoids and heat-processed foods. However, due to the contradictory nature of the results quercetin, one of the most active flavonols in vitro, was investigated under in vivo conditions using the micronucleus and host-mediated tests. Per os administration of up to 1 g / k g quercetin was negative in both tests. Furthermore, a complementary motility study revealed that quercetin was present at the site of degradation 2 - 4 h after ingestion. These results suggest that insufficient quercetin (or its metabolites) were absorbed to exert an effect in vivo. An extensive study of Maillard reaction models using the Ames test revealed that pH, water content, amino acid:sugar ratio, temperature and reaction time all influenced the mutagenic outcome. In fact these factors were all interrelated. Of importance for risk assessment is the observation that severely heat-treated foods are metabolically activated whereas moderately treated food products are deactivated.
Agurell, E., Department of Radiobiology, Wallenberg Laboratory, University of Stockholm, S-106 91 Stockholm (Sweden)
Variations of the mutagenic impurities in a carbon black Various types of carbon black (CB) are used as rubber additives and as colorants in printing, photocopying, typewriting and carbon copying. CB may contain mutagenic impurities mainly consisting of a complex mixture of polycyclic aromatic hydrocarbons when the CB has not been exposed to an oxidative after-treatment (Agurell and L~froth, in: Short-term Bioassays in the Analysis of Complex Environmental Mixtures III, Plenum, New York, 1982). Commercial batches of a particular type of CB have been sampled regularly during 1 year in order to assess the long-term variations of mutagenic impurities and their possible correlation to production parameters. The CB has been extracted with benzene and the extracted impurities have been dissolved in dimethyl sulfoxide. The mutagenicity has been determined with the Salmonella/microsome assay with strains TA98 and TA100. The CB, being of a type used as rubber additive and as colorant in newspaper printing ink, generally contains some mutagens which are detectable in the absence of mammalian metabolic activation; the response of these impurities is about 1-4 revertants per mg CB in TA98. The major part of the mutagenic impurities is, however, of a type requiring mammalian metabolic activation ($9). The response of this type of mutagens has
221
European Environmental Mutagen Society Abstracts of papers presented at the 12th Annual Meeting of EEMS on Mutagens in our Environment, June 20th-24th, 1982, Dipoli, Espoo (Finland)
Adler, I.-D., Institute of Genetics, GSF, D-8042 Neuherberg (F.R.G.) Germ-cell sensitivity in mammals
A characteristic feature of chemical mutagens is their differential spermatogenic response to mutation induction (Ehling, Mutation Res., 26 (1974) 285). Dominant lethal mutations and, in many cases correspondingly, heritable translocation induction follows a particular sensitivity pattern for various chemicals in post-spermatogonial germ cells (Generos 0 et al., Mutation Res., 76 (1980) 191). Chemically induced gross chromosomal changes in spermatogonia are eliminated by germinal selection (Adler, in: Cytogenetic Assays of Environmental Mutagens, Allanheld, Osmun, 1982, p. 249). In contrast, gene mutations are transmitted from stem-cell spermatogonia through meiosis to the offspring. In the specific-locus test mitomycin C and ethylnitrosourea are most effective in spermatogonia and ineffective in post-spermatogonial stages (Ehling et al., Mutation Res., 92 (1982) 181). Cyclophosphamide and methyl methanesulfonate react in the opposite way (Russell, L.B. et al., Mutation Res., 86 (1981) 329). Procarbazine and triethylenemelamine are effective in both types of germ cells, however, with different mutation rates (Ehling, Arch. Toxicol., 46 (1980) 123). Differences in oocyte sensitivity have been observed with mitomycin C and procarbazine. The response to induction of specific-locus mutations in oocytes was lower than in spermatogonia (Ehling, in: Environmental Mutagens and Carcinogens, University of Tokyo Press, 1982, p. 709). These differences in mammalian germ-cell sensitivity are an important factor for the evaluation of genetic hazards due to human chemical exposure.
2 Aeschbacher, H.U., Nestl~ Research Department, CH-1814 La Tour-de Peilz (Switzerland)
0165-1161/83/0000-0000/$03.00 © 1983 ElsevierSciencePublishers
222
The significance of mutagens in food Recently numerous in vitro mutagenicity investigations have been carried out on foods. They have mainly focused on the effects of naturally occurring flavonoids and heat-processed foods. However, due to the contradictory nature of the results quercetin, one of the most active flavonols in vitro, was investigated under in vivo conditions using the micronucleus and host-mediated tests. Per os administration of up to 1 g / k g quercetin was negative in both tests. Furthermore, a complementary motility study revealed that quercetin was present at the site of degradation 2 - 4 h after ingestion. These results suggest that insufficient quercetin (or its metabolites) were absorbed to exert an effect in vivo. An extensive study of Maillard reaction models using the Ames test revealed that pH, water content, amino acid:sugar ratio, temperature and reaction time all influenced the mutagenic outcome. In fact these factors were all interrelated. Of importance for risk assessment is the observation that severely heat-treated foods are metabolically activated whereas moderately treated food products are deactivated.
Agurell, E., Department of Radiobiology, Wallenberg Laboratory, University of Stockholm, S-106 91 Stockholm (Sweden)
Variations of the mutagenic impurities in a carbon black Various types of carbon black (CB) are used as rubber additives and as colorants in printing, photocopying, typewriting and carbon copying. CB may contain mutagenic impurities mainly consisting of a complex mixture of polycyclic aromatic hydrocarbons when the CB has not been exposed to an oxidative after-treatment (Agurell and L~froth, in: Short-term Bioassays in the Analysis of Complex Environmental Mixtures III, Plenum, New York, 1982). Commercial batches of a particular type of CB have been sampled regularly during 1 year in order to assess the long-term variations of mutagenic impurities and their possible correlation to production parameters. The CB has been extracted with benzene and the extracted impurities have been dissolved in dimethyl sulfoxide. The mutagenicity has been determined with the Salmonella/microsome assay with strains TA98 and TA100. The CB, being of a type used as rubber additive and as colorant in newspaper printing ink, generally contains some mutagens which are detectable in the absence of mammalian metabolic activation; the response of these impurities is about 1-4 revertants per mg CB in TA98. The major part of the mutagenic impurities is, however, of a type requiring mammalian metabolic activation ($9). The response of this type of mutagens has