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Mutagenic activity of organochlorine compounds in effluents from bleacheries
140 in all four tissues, in the treated ones the spleen seems to have a higher induced SCE frequency than other tissues.
64 Mohn, G.R. a, N. Guijt b and B.W. Glickman b, a Department of Radiation Genetics and Chemical Mutagenesis, and b Laboratory for Molecular Genetics, Leiden State University, Leiden (The Netherlands) Influence of DNA adenine methylation (DAM) mutations and of R plasmid pKM101 on the spontaneous and induced mutability of certain genes in E. coli K12 The dependence of spontaneous and induced mutation spectra on changes of genetic background, e.g. of enzymes regulating DNA metabolism and repair was studied in E. coli K12 to gain information on mechanisms of mutation induction and to possibly increase sensitivity to certain mutagens. The R plasmid pKM101 as well as the dam-3 and dam-4 mutations were introduced separately or jointly in strain 343/113 in which forward mutations in several genes and mutagen specific back mutations in two genes can be detected simultaneously. In confirmation of previous results, spontaneous mutability of all mutation systems tested (galR-, MTR, Arg +, and nad +) is enhanced in the dam-3 and dam-4 derivatives, especially at the arg56 locus while the introduction of pKM101 leads to a slight increase in spontaneous mutation only in the 5-methyltryptophane (MTR) resistance system. The presence of pKM101, however, increases significantly the yield of mutations induced by the 2-nitrofuran derivative AF-2 and the alkylating agent methyl methanesulfonate. Furthermore, mutation induction b y ethyl methanesulphonate is more pronounced in pKM101 strains as is also found in the dam-4 derivative. In the E. coli 343/113 substrains carrying both pKM101 and a dam mutation, mutation induction appears to be higher than in the individual parent strains b u t a reduced growth capacity (leading to smaller mutant colonies) makes accurate quantitative comparisons difficult. In spot tests, however, the changes of sensitivity toward the mutagenic action of 9-aminoacridine can be easily demonstrated: moderate activity in inducing nad÷ back mutation in E. coli 343/113, slightly enhanced activity in the pKM101 derivative, high activity in the dam-4 background and extremely high activity in the pKMlO1/dam-4 combination.
65 MSller, M., and S.E. Fevolden, Central Institute for Industrial Research, Blindern, Oslo 3 (Norway)
Mutagenic activity of organochlorine compounds in effluents from bleacheries Effluents from chlorine bleacheries in sulphite and sulphate paper plants contain substances with acute toxic, sublethal and mutagenic effects. The different stages in the bleaching process have been investigated. Extraction of the
141
effluents at pH = 11 and pH = 2 with cyclohexan and butylacetate respectively, gave a nonpolar and a medium-polar fraction. Some of the identified compounds in each fraction were synthesized and tested separately with Ames' Salmonella strains. These polar and nonpolar halogenated, low molecular weight c o m p o u n d s produced base-pair substitutions in TA 1535 and TA 100. Most of the activity was connected to substances identified in the polar fractions. Liver microsomes did lower the activity somewhat in most cases. The synthesized c o m p o u n d s will be tested in the DNA repair test with E. coli (polA ÷ polA-) and their ability to transform mammalian cells in vitro will be investigated.
66 Monti-Bragadin, C., S. Venturina and M. Tamaro, Institute of Microbiology, University of Trieste, Trieste (Italy)
An improvement in the sensitivity of polymerase I deficient Escbericbia coli for detecting mutagens and carcinogens In order to improve the sensitivity of the DNA polymerase I deficient assay for detecting mutagens and carcinogens, a strain was prepared carrying the l e x A - mutation and the R391 plasmid in addition to the poIA allele. This strain, named TM1080, was found to be much more sensitive than wild-type or polA- strains to a number of DNA modifying agents, b u t not to antibacterial substances acting by mechanisms other than interaction with DNA. Tests based on sensitivity of TM1080 can be carried out by agar diffusion or in liquid medium. Metabolic activation can be used in liquid culture where necessary.
67 Neuh/~user, A., Abteilung ffir Genetik, GSF, D-8042 Neuherberg (West-Germany) Comparison between chemically and radiation-induced specific-locus mutations in spermatogonia o f the mouse With the specific-locus method recessive gene mutations at 7 loci are recovered in the first generation after treatment. In various experiments 39 specificlocus mutations were observed with procarbazine, 14 with mitomycin C, 50 with X-irradiation, and 10 in the controls. Comparing the distribution of mutations among the 7 tested loci, marked differences are recognizable between the chemically and radiation-induced mutations. In the chemical experiments the majority of mutations were at the b and p loci, together forming 53% of the total as against 24% in the radiation series. 11% s mutations were found after chemical treatment, whereas 36% o f all radiation-induced mutations were of this type. 3 se mutations were observed in the procarbazine experiments, b u t no simultaneous d and se mutations, although there were 5 of this t y p e in the radiation series. Breeding tests of 71 mutants proved that 24% (7/29) of the
64 Mohn, G.R. a, N. Guijt b and B.W. Glickman b, a Department of Radiation Genetics and Chemical Mutagenesis, and b Laboratory for Molecular Genetics, Leiden State University, Leiden (The Netherlands) Influence of DNA adenine methylation (DAM) mutations and of R plasmid pKM101 on the spontaneous and induced mutability of certain genes in E. coli K12 The dependence of spontaneous and induced mutation spectra on changes of genetic background, e.g. of enzymes regulating DNA metabolism and repair was studied in E. coli K12 to gain information on mechanisms of mutation induction and to possibly increase sensitivity to certain mutagens. The R plasmid pKM101 as well as the dam-3 and dam-4 mutations were introduced separately or jointly in strain 343/113 in which forward mutations in several genes and mutagen specific back mutations in two genes can be detected simultaneously. In confirmation of previous results, spontaneous mutability of all mutation systems tested (galR-, MTR, Arg +, and nad +) is enhanced in the dam-3 and dam-4 derivatives, especially at the arg56 locus while the introduction of pKM101 leads to a slight increase in spontaneous mutation only in the 5-methyltryptophane (MTR) resistance system. The presence of pKM101, however, increases significantly the yield of mutations induced by the 2-nitrofuran derivative AF-2 and the alkylating agent methyl methanesulfonate. Furthermore, mutation induction b y ethyl methanesulphonate is more pronounced in pKM101 strains as is also found in the dam-4 derivative. In the E. coli 343/113 substrains carrying both pKM101 and a dam mutation, mutation induction appears to be higher than in the individual parent strains b u t a reduced growth capacity (leading to smaller mutant colonies) makes accurate quantitative comparisons difficult. In spot tests, however, the changes of sensitivity toward the mutagenic action of 9-aminoacridine can be easily demonstrated: moderate activity in inducing nad÷ back mutation in E. coli 343/113, slightly enhanced activity in the pKM101 derivative, high activity in the dam-4 background and extremely high activity in the pKMlO1/dam-4 combination.
65 MSller, M., and S.E. Fevolden, Central Institute for Industrial Research, Blindern, Oslo 3 (Norway)
Mutagenic activity of organochlorine compounds in effluents from bleacheries Effluents from chlorine bleacheries in sulphite and sulphate paper plants contain substances with acute toxic, sublethal and mutagenic effects. The different stages in the bleaching process have been investigated. Extraction of the
141
effluents at pH = 11 and pH = 2 with cyclohexan and butylacetate respectively, gave a nonpolar and a medium-polar fraction. Some of the identified compounds in each fraction were synthesized and tested separately with Ames' Salmonella strains. These polar and nonpolar halogenated, low molecular weight c o m p o u n d s produced base-pair substitutions in TA 1535 and TA 100. Most of the activity was connected to substances identified in the polar fractions. Liver microsomes did lower the activity somewhat in most cases. The synthesized c o m p o u n d s will be tested in the DNA repair test with E. coli (polA ÷ polA-) and their ability to transform mammalian cells in vitro will be investigated.
66 Monti-Bragadin, C., S. Venturina and M. Tamaro, Institute of Microbiology, University of Trieste, Trieste (Italy)
An improvement in the sensitivity of polymerase I deficient Escbericbia coli for detecting mutagens and carcinogens In order to improve the sensitivity of the DNA polymerase I deficient assay for detecting mutagens and carcinogens, a strain was prepared carrying the l e x A - mutation and the R391 plasmid in addition to the poIA allele. This strain, named TM1080, was found to be much more sensitive than wild-type or polA- strains to a number of DNA modifying agents, b u t not to antibacterial substances acting by mechanisms other than interaction with DNA. Tests based on sensitivity of TM1080 can be carried out by agar diffusion or in liquid medium. Metabolic activation can be used in liquid culture where necessary.
67 Neuh/~user, A., Abteilung ffir Genetik, GSF, D-8042 Neuherberg (West-Germany) Comparison between chemically and radiation-induced specific-locus mutations in spermatogonia o f the mouse With the specific-locus method recessive gene mutations at 7 loci are recovered in the first generation after treatment. In various experiments 39 specificlocus mutations were observed with procarbazine, 14 with mitomycin C, 50 with X-irradiation, and 10 in the controls. Comparing the distribution of mutations among the 7 tested loci, marked differences are recognizable between the chemically and radiation-induced mutations. In the chemical experiments the majority of mutations were at the b and p loci, together forming 53% of the total as against 24% in the radiation series. 11% s mutations were found after chemical treatment, whereas 36% o f all radiation-induced mutations were of this type. 3 se mutations were observed in the procarbazine experiments, b u t no simultaneous d and se mutations, although there were 5 of this t y p e in the radiation series. Breeding tests of 71 mutants proved that 24% (7/29) of the