Possible mutagenic activity of saccharin

Summary A mutagenic effect of saccharin in Chinese hamsters, using the in vivo SCE test, was observed when massive overdoses were administered; cyclamate was not mutagenic.     

Long-lasting persistence of elevated sister-chromatid exchange frequencies induced by perinatal benzo(a)pyrene treatment in rat bone-marrow cells

In this work the possibility that a mutagenic factor acting in utero or in the perinatal period might lead to elevated mutagenic rates in bone-marrow cells after a considerable period of time was examined. An aromatic hydrocarbon, benzo(a)pyrene was used as the test substance. Benzo(a)pyrene treatments resulted in significantly higher sister-chromatid exchange (SCE)-frequencies in both fetal and neonatal groups in both sexes, even four months after exposure. In a second experiment we examined whether mutagenic exposure suffered in utero could make the individual more susceptible to mutagenic effects in adulthood. Preliminary results indicate that such a possibility could exist.     

Mutagenicity and toxicity of chloroethylene oxide and chloroacetaldehyde

Exposure of several trp-auxotrophic Escherichia coli strains, carrying base-pair substitutions, to chloroethylene oxide or chloroacetaldehyde (two metabolites of vinyl chloride) increased the mutation frequency to tryptophan prototrophy. Strong cytotoxic and mutagenic effects were observed with 2.5 mM chloroethylene oxide, while a higher concentration of chloroacetaldehyde (100 mM) exhibited a mutagenic effect which was 400 times lower.     

Mutagenicity and toxicity of chloroethylene oxide and chloroacetaldehyde

Summary Exposure of severaltrp-auxotrophicEscherichia coli strains, carrying base0pair substitutions, to chloroethylene oxide or chloroacetaldehyde (two metabolites of vinyl chloride) increased the mutation frequency to tryptophan prototrophy. Strong cytotoxic and mutagenic effects were observed with 2.5 mM chloroethylene oxide, while a higher concentration of chloroacetaldehyde (100 mM) exhibited a mutagenic effect which was 400 times lower.I am grateful to Prof. G. Michel, Laboratoire de Biochimie Microbienne, and to Dr H. Bartsch, International Agency for Research on Cancer, for the support of this work. I wish to thank Dr F. Besson-Simien and Dr A. Barbin for their collaboration.     

N-Nitrosospermidine: the principal nitrosation product of spermidine

Summary N-(4-Aminobutyl)-N-(3-aminopropyl)nitrosamine (N-nitrosospermidine) was identified as a major product in the reaction between spermidine and nitrous acid. N-Nitrosospermidine was not significantly mutagenic in the Ames assay.Acknowledgment. This work was supported in part by a Grant-in-Aid for Cancer Research (50-2) from the Ministry of Health and Welfare of Japan.     

Studies on benzene mutagenesis. I. The micronucleus test

Summary The mutagenic action of benzene was studied by means of the micronucleus test performed on mice. A linear dose effect relationship was found for the percentage of micronucleated erythrocytes, against the benzene-dose logarithms. A significant dose effect correlation was found either after the standard 30-h experiments or after a prolonged 54-h one. A higher effect was found in the prolonged experiments, suggesting the induction of a delay in the cell cycle by benzene.     

Mutagenic activity of sodium bisulphite in barley

Summary Sodium bisulphite (7 and 10 mM) treatments administered at 30°C for 6 h have been found to be strongly mutagenic in barley.     

Sporeless mutants of Bacillus thuringiensis. II. mutants derived from var. thuringiensis and var. sotto.

Three sporeless mutants of Bacillus thuringiensis, 2 derived from var. thuringiensis and 1 from var. sotto were selected after mutagenic treatment. They were completely lacking in ability to form spores, yet maintained intact insecticidal activity.     

In vitro mutagenicity of the soil nematicide 1,3-dichloropropene.

The cis- and trans-isomers of 1,3-dichloropropene have been tested in the Ames mutagenicity assay system on Salmonella typhimurium tester strain TA 1535. Both isomers have been found to be mutagenic even without microsomal activation.     

Mammalian spot test with moxnidazole, a 5-nitroimidazole

Moxnidazole [3-(5-nitrol-1-methyl-2-imidazolyl)-methyleneamino-5-morpholinomethyl-2-oxazolidinone, HCl], known to be mutagenic in microbial tests and Drosophila, induced genetic alterations in somatic cells of mice. Ethyl methanesulfonate (EMS) served as positive control.     

Dominant lethal mutations induced by14C in mice

Summary The mutagenic potential of 1.0 Ci¹⁴C was evaluated in Swiss albino male mice by the dominant lethal assay. A significant increase in post-implantation loss was seen, the maximum being in the 3rd week after treatment.Authors express their thanks to University Grants Commission, New Delhi, for financial assistance.     

Action of alkylating agents on nitrogen fixation by clones of Anabaena doliolum Bharadwaja

Summary The physiological and mutagenic actions of three alkylating agents have been studied on the process of nitrogen fixation byAnabaena doliolum Bharadwaja. The results show that these chemicals presumably switch off the activity of nitrogenase, resulting in the inhibition of fixation.     

Conversion of psoralen DNA monoadducts in E. coli to interstrand DNA cross links by near UV light (320-360 nm): inability of angelicin to form cross links, in vivo.

Both angelicin and psoralen monoadducts formed in vivo in E. coli by near UV light produce lethal and mutagenic effects. However psoralen monoadducts are converted to cross links by higher doses of UV; angelicin monoadducts are not. The relevance of these results to psoralen photosensitization is discussed.     

Evidence for enzymatic reduction of 1-nitropyrene by rat liver fractions

Summary 1-Nitropyrene, a mutagenic compound found in diesel exhaust and photocopy toners, is reduced anaerobically by rat liver fractions to 1-aminopyrene. This reaction is stimulated in the microsomal fraction by NADPH and in the cytosol by FMN. Addition of both cofactors produced more reduction in S-9, microsomes, or cytosol than either cofactor alone.     

Conversion of psoralen DNA monoadducts in E. coli to interstrand DNA cross links by near UV light (320–360 nm): Inability of angelicin to form cross links,in vivo

Summary Both angelicin and psoralen monoadducts formed in vivo in E. coli by near UV light produce lethal and mutagenic effects. However psoralen monoadducts are converted to cross links by higher doses of UV; angelicin monoadducts are not. The relevance of these results to psoralen photosensitization is discussed.Supported by the National Research Council of Canada.     

Penicillium auxotrophic mutants can be detected by suing xanthene dyes

Summary Auxotrophic mutants ofPenicillium spp. have been directly isolated after mutagenic treatment from agar plates containing Xanthene dyes. They grow as characteristic small colored colonies. Some strains were tested and they showed a differential response depending on the Xanthene dye used.     

Antischistosomal and some toxicological properties of a nitrodiphenylaminoisothiocyanate (C 9333-Go/CGP 4540).

A procedure to enhance the schistosomicidal effectiveness in vivo of an isothiocyanate derivative and some of its antischistosomal properties are reported. Determinations of the effects of this compound on tissue thiol levels and on highly sensitivity bacterial tester strains have indicated that its mutagenic potential is of a low order and that the latter is decreased further after reduction of the host's intestinal bacterial flora.     

Chemische Konstitution und mutagene Wirkung. Klassifizierungsversuch chemischer Mutagene

Summary Chemical mutagens were classified with regard to the relationship between their chemical constitution and their mutagenic activity. Within the single groups possible common modes of action were considered. For alkylating mutagens, both the significance of the reactive groups and of the basal compounds, and a possible mutation mechanism weare discussed.     

In vitro mutagenicity of the soil nematicide 1,3-dichloropropene

Summary The cis- and trans-isomers of 1,3-dichloropropene have been tested in the Ames mutagenicity assay system on Salmonella typhimurium tester strain TA 1535. Both isomers have been found to be mutagenic even without microsomal activation.Acknowledgment. We wish to thank Mrs J. Ahamer for excellent technical help. We are also grateful to Deutsche Shell GmbH., Frankfurt, for their kind assistance in providing samples.