E U R O P E A N E N V I R O N M E N T A L MUTAGEN SOCIETY
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lase into a polybenzimidazole ribonucleotide. Addition of radioactive amino acids to this system and blocking of the normal mRNA synthesis by actinomycin D results in the formation of peptides containing only asparagine (codon AAPy), arginine (codon AGPu), lysine (codon AAPu) and serine (codon AGPy), respectively. Experiments with desoxyribo-homopolymers as templates showed however, that BTP is used by RNA polymerase only in the presence of poly dC, i.e. it is incorporated into RNA instead of guanine, but is read during translation (a) in the first codon position as adenine (b) in the second codon position as purine and (c) in the third codon position as base. These findings are consistent with the earlier observation that the benzimidazole-induced growth inhibition in microorganisms can especially well be reversed by guanine. This research is supported by grant No. 3.7o4o.7 2 of the Swiss National Foundation for Scientific Research.
36 SIDERIS, E. G., AND M. ARGYRAKIS,Biology Division, Nuclear Research Center Democritos, Athens (Greece).
The effect of the potent mutagen azide on deoxyribonucleic acid Sodium azide is a potent nmtagen, whose nmtagenic action is not associated with chromosonle aberrations. During incubation of deoxyribonucleosides in the presence of hydrogen azide, the conjugated acid of the sodium azide, a fivefold increase in the liberation of adenine and guanine was observed over that in the presence of hydrochloric acid of the same acidity. Similar results were found with deoxyribonucleotides and salmon sperm deoxyribonucleic acid. These results could explain, at least partially, the mutagenic effect of azide on the basis of a base-substitution mechanism.
37 VIG, B. K., Department of Biology, University of Nevada, Reno, Nev. 89507 (U.S.A.) Soybean (Glycine max): a new test system for study of genetic parameters as affected by environmental mutagens The light green YnYu, plants of varietis T2I 9 and L65-I237 of soybean have some dark green, yellow and twin (or double) spots resembling the phenotypes controlled by YuYn, ynYn and Y n Y n - Y n y n genotypes, respectively. The process of somatic crossing over is considered responsible for origin of double spots. The single spots may originate by failure of one of the two components of the double spots or by processes involving non-disjunction, paramutations and controlling elements, point mutations, chloroplastic DNA, etc. Several mutagens increase the frequency of the three types of spots, either equally or differentially. It is suggested that the pattern of action of a given mutagen can be studied by analyzing the relative increase of different types of spots.
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When plants of the genotype 3'93'9 are raised from seed treated with caffeine or mitomycin C the three types of spots, as observed on Yn3'n material, are found. This data leads to conclusion that }"9 and Ylt are not two loci but that Y,, and Y.q are the same, and 3'9 is allelic to Y9 (or Yn) and hence also to 3',,.
38 VOOGD, C. E., National Institute of Public Health, Utrecht (The Netherlands)
Nitroi midazoles, a new class of mutagenic agents. The mutagenic action has been investigated of the following nitroimidazoles and some other imidazoles: ronidazole, metronidazole, dimetridazole, nimorazole, 5methyl-4-nitroimidazole, panidazole, tinidazole, 4-nitroimidazole, 2-methyl-4-nitroimidazole, 2-isopropyl-4-nitroimidazole, I-methylinfidazole, 2-methylimidazole, 1,2dimethylimidazole, i-ethylimidazole and imidazole. LURIA AND DELBRf'CK'S fluctuation test was applied using streptomycin resistance as a marker. The test organisms used were an auxotrophic strain of Klebsiella pneumoniae, requiring uracil and proline for growth, Escherichia coli K~2"Hfr Hayes and Citrobacter freundii 425 . The mutation rate of the above substances was deternfined on concentrations generally ranging from I mM and o.oi raM. Using Klebsiella pneumoniae, ronidazole, at the level of o.I raM, showed an increase of the nmtation rate of 26. 5 in comparison of the spontaneous rate of mutation. Similarly, metronidazole, dimetridazole, nimorazole, tinidazole, panidazole and 5-methyl-4-nitroimidazole, at the level of (i.1 raM, increased the mutation rate by a factor of between 3 and 7. In the same way 4-nitroimidazole, at a concentration of I m'lI, increased the mutation rate by a factor of 3, whereas solutions of IO mM of 2-metlLvl-4-nitroimidazole and 2-isopropyl-4-nitroimidazole increased the mutation rate by a factor of 3 or 4. As far as examined, the other imidazoles appeared to be non-mutagenic under the conditions of our experinlents.
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lase into a polybenzimidazole ribonucleotide. Addition of radioactive amino acids to this system and blocking of the normal mRNA synthesis by actinomycin D results in the formation of peptides containing only asparagine (codon AAPy), arginine (codon AGPu), lysine (codon AAPu) and serine (codon AGPy), respectively. Experiments with desoxyribo-homopolymers as templates showed however, that BTP is used by RNA polymerase only in the presence of poly dC, i.e. it is incorporated into RNA instead of guanine, but is read during translation (a) in the first codon position as adenine (b) in the second codon position as purine and (c) in the third codon position as base. These findings are consistent with the earlier observation that the benzimidazole-induced growth inhibition in microorganisms can especially well be reversed by guanine. This research is supported by grant No. 3.7o4o.7 2 of the Swiss National Foundation for Scientific Research.
36 SIDERIS, E. G., AND M. ARGYRAKIS,Biology Division, Nuclear Research Center Democritos, Athens (Greece).
The effect of the potent mutagen azide on deoxyribonucleic acid Sodium azide is a potent nmtagen, whose nmtagenic action is not associated with chromosonle aberrations. During incubation of deoxyribonucleosides in the presence of hydrogen azide, the conjugated acid of the sodium azide, a fivefold increase in the liberation of adenine and guanine was observed over that in the presence of hydrochloric acid of the same acidity. Similar results were found with deoxyribonucleotides and salmon sperm deoxyribonucleic acid. These results could explain, at least partially, the mutagenic effect of azide on the basis of a base-substitution mechanism.
37 VIG, B. K., Department of Biology, University of Nevada, Reno, Nev. 89507 (U.S.A.) Soybean (Glycine max): a new test system for study of genetic parameters as affected by environmental mutagens The light green YnYu, plants of varietis T2I 9 and L65-I237 of soybean have some dark green, yellow and twin (or double) spots resembling the phenotypes controlled by YuYn, ynYn and Y n Y n - Y n y n genotypes, respectively. The process of somatic crossing over is considered responsible for origin of double spots. The single spots may originate by failure of one of the two components of the double spots or by processes involving non-disjunction, paramutations and controlling elements, point mutations, chloroplastic DNA, etc. Several mutagens increase the frequency of the three types of spots, either equally or differentially. It is suggested that the pattern of action of a given mutagen can be studied by analyzing the relative increase of different types of spots.
240
4TH ANNUAL MEETING, HEII)ELBERG
When plants of the genotype 3'93'9 are raised from seed treated with caffeine or mitomycin C the three types of spots, as observed on Yn3'n material, are found. This data leads to conclusion that }"9 and Ylt are not two loci but that Y,, and Y.q are the same, and 3'9 is allelic to Y9 (or Yn) and hence also to 3',,.
38 VOOGD, C. E., National Institute of Public Health, Utrecht (The Netherlands)
Nitroi midazoles, a new class of mutagenic agents. The mutagenic action has been investigated of the following nitroimidazoles and some other imidazoles: ronidazole, metronidazole, dimetridazole, nimorazole, 5methyl-4-nitroimidazole, panidazole, tinidazole, 4-nitroimidazole, 2-methyl-4-nitroimidazole, 2-isopropyl-4-nitroimidazole, I-methylinfidazole, 2-methylimidazole, 1,2dimethylimidazole, i-ethylimidazole and imidazole. LURIA AND DELBRf'CK'S fluctuation test was applied using streptomycin resistance as a marker. The test organisms used were an auxotrophic strain of Klebsiella pneumoniae, requiring uracil and proline for growth, Escherichia coli K~2"Hfr Hayes and Citrobacter freundii 425 . The mutation rate of the above substances was deternfined on concentrations generally ranging from I mM and o.oi raM. Using Klebsiella pneumoniae, ronidazole, at the level of o.I raM, showed an increase of the nmtation rate of 26. 5 in comparison of the spontaneous rate of mutation. Similarly, metronidazole, dimetridazole, nimorazole, tinidazole, panidazole and 5-methyl-4-nitroimidazole, at the level of (i.1 raM, increased the mutation rate by a factor of between 3 and 7. In the same way 4-nitroimidazole, at a concentration of I m'lI, increased the mutation rate by a factor of 3, whereas solutions of IO mM of 2-metlLvl-4-nitroimidazole and 2-isopropyl-4-nitroimidazole increased the mutation rate by a factor of 3 or 4. As far as examined, the other imidazoles appeared to be non-mutagenic under the conditions of our experinlents.
