Biotransformation and toxicity of aniline and aniline derivatives in cyanobacteria

Agmenellum quadruplicatum strain PR-6 and Oscillatoria sp. strain JCM grown photoautotrophically in the presence of aniline metabolized the aromatic amine to formanilide, acetanilide and p-aminophenol. The metabolites were isolated by either thin-layer, gas-liquid or high pressure liquid chromatography and identified by comparison of their chromatographic, ultraviolet absorbance and mass spectral properties with those of authentic compounds. The toxicity of aniline derivatives towards Agmenellum quadruplicatum strain PR-6 indicated that the cyanobacterium was extremely sensitive to o-, m- and p-aminophenols, and phenylhydroxylamine.Abbreviations TLC thin layer chromatography - HPLC high pressure liquid chromatography - GC/MS gas chromatography/mass spectrometry - m/e mass to charge ratio     

Genotoxicity of zinc in 4 short-term mutagenicity assays

The genotoxicity of zinc was examined in 4 short-term mutagenicity assays. Zinc acetate produced dose-related positive responses in the L5178Y mouse lymphoma assay and an in vitro cytogenetic assay with Chinese hamster ovary cells, but was negative in the Salmonella mutation assay and did not induce unscheduled DNA synthesis in primary cultures of rat hepatocytes. Zinc-2,4-pentanedione produced frameshift mutations in Salmonella tester strains TA1538 and TA98, but did not induce unscheduled DNA synthesis in primary cultures of rat hepatocytes. The effect of ligand binding of zinc in the in vitro test systems is discussed.     

Genotoxicity of cocoa in a series of short-term assays

Cocoa powder was evaluated for genotoxic activity and found to be inactive in the Ames assay, the mouse lymphoma assay, cytogenetic assays measuring chromosome breakage and SCE, and a cell transformation assay using Balb/c-3T3 cells. Although pure theobromine has been shown to be active in some of these test procedures, the levels of this methylxanthine present in cocoa powder were insufficient to elicit responses in this battery of tests.     

Genotoxicity of theobromine in a series of short-term assays

Theobromine (3,7-dimethylxanthine) was evaluated for genotoxic activity in a series of in vitro assays. Theobromine was not mutagenic in the Ames assay up to a maximum concentration of 5000 micrograms/plate either with or without S9 activation. The compound also failed to induce significant levels of chromosome aberrations in CHO cells (with and without S9 activation) or transformation in Balb/c-3T3 cells. At the maximum tolerated concentration theobromine increased the frequency of TK-/- mutants in mouse lymphoma L5178Y cells. Increased frequencies were observed both with and without S9 activation and they were reproducible in 2 independent experiments. Statistically significant increases in SCEs were obtained in human lymphocytes and in CHO cells under nonactivation test conditions. The spectrum of results in this battery of tests indicate that theobromine treatment results in the expression of genotoxic potential in some assays and the observed activity appears qualitatively and quantitatively similar to that of caffeine, a closely related methylxanthine.     

Characteristics of the formation of short-term memory in rats at various time intervals between tests

Dependency of the speed of short-term memory formation in rats on the intertrial interval was studied. The so called direct method was applied for determining the delay time of the complex perception of food location. Conclusion is made that not less than 2 minutes intertrial intervals appear to be optimal for the formation of short-term memory. Such behavioural manifestations as omission of separate trials, lengthening of the time both for grooming and running to the feeder are considered to the manifestation of brain self-regulation activity. Attention is paid to the fact that such a form of behaviour is characteristic of one group of rats and not of the other.     

Genotoxicity testing of five compounds in three Drosophila short-term somatic assays

To provide further background data for the somatic mutation and/or recombination tests in Drosophila melanogaster, we have evaluated the responses in 3 assyas (zeste-white, white-ivory and wing spot) of 5 chemicals classified by the U.S. National Toxicology Program (NTP) as genotoxic non-carcinogens (or ambiguous). The selected compounds were 2-chloromethylpyridine, 1-nitronaphthalene, 4-nitro-o-phenylenediamine, 3-nitropropionic acid and p-phenylenediamine. Our results show that all the compounds tested produce significant increases in the frequency of mutant clones, in at least one of the assays, p-phenylenediamine being the compound which present a clearer mutagenic activity, and the wing spot test, the assay the detects more genotoxic compounds (4/5).     

Genotoxicity of beryllium, gallium and antimony in short-term assays.

The genotoxicity of beryllium, gallium and antimony compounds was studied with the rec, Salmonella mutagenicity and SCE assays. In the rec assay, all the salts of the metals, BeCl2, Be(NO3)2, GaCl3, Ga(NO3)3, SbCl3, SbCl5, and an oxide, Sb2O3, had DNA-damaging activity. None of the compounds was mutagenic to Salmonella. In the SCE assays using V79 cells, 2 antimony(III) compounds, SbCl3 and Sb2O3, and 2 beryllium compounds, BeCl2 and Be(NO3)2, induced SCEs significantly. Sb2O3, slightly soluble in water, was positive in both the rec assay and the SCE assay at very low doses.     

The fluorescence of indoles and aniline derivatives

1. The variations in the excitation and fluorescence wavelengths and fluorescence intensities of a number of indole and aniline derivatives over a wide range of acidity and alkalinity (36n-sulphuric acid to 10n-potassium hydroxide) have been studied. 2. The changes in fluorescence with pH of the indoles and anilines had many characteristics in common, and the most fluorescent species were found to be the non-ionized or neutral forms showing fluorescence maxima at about lambda 350mmu. 3. In 10n-potassium hydroxide most of the compounds examined, except those containing a tertiary nitrogen atom, showed a bathochromic shift in fluorescence wavelength attributable to an anion due to a negatively charged nitrogen, but in strong acid (3n-sulphuric acid) these compounds were non-fluorescent, except the anisidines and the 5-hydroxyindoles. 4. p-Anisidine but not the o- and m-isomers showed excited-state ionization in acid solution. 5. Of the hydroxyindoles only the 5-hydroxy derivatives showed a fluorescence (lambda(max.) 520-540mmu) in acid solution. It is suggested that this fluorescence is due to a proton-transfer reaction in the excited state, and various arguments for this suggestion are given. 6. Stokes shifts for the various ionic and neutral species of the indoles and anilines have been calculated, and the large shifts found with indole and p-anisidine may be due to solvent-solute interaction.     

Biomonitoring of arylamines: haemoglobin adducts of aniline derivatives

Aromatic amines are important intermediates in industrial manufacturing. They are used in a large number of products, such as pesticides, dyes, plastics and pharmaceuticals. The parent arylamines can be metabolically released from these arylamine-based compounds and form DNA and protein adducts after N-oxidation to N-hydroxy arylamines. Aromatic amine derivatives, including the industrial intermediates acetoacetanilide, acetoacet-m-xylidide and N-ethylaniline, were examined for their ability to form Hb adducts in rats as potential biomarkers of exposure. The haemoglobin binding indices (HBI=binding [mmol mol^-1 Hb]/dose [mmol kg^-1 body weight]) of the arylamines were determined 24 h after oral administration to female Wistar rats. The precipitated haemoglobin was dissolved in 0.1 M sodium hydroxide in the presence of internal standards. After hexane extraction the released arylamines were analysed by gas chromatography-mass spectrometry (GC-MS). For aniline released from acetoacetanilide an HBI of 15 and for 2,4-dimethylaniline released from acetoacet-m-xylidide an HBI of 0.129 were determined. The HBIof aniline released from N-ethylaniline was 45.     

Biomonitoring of arylamines: haemoglobin adducts of aniline derivatives

Aromatic amines are important intermediates in industrial manufacturing. They are used in a large number of products, such as pesticides, dyes, plastics and pharmaceuticals. The parent arylamines can be metabolically released from these arylamine-based compounds and form DNA and protein adducts after N-oxidation to N-hydroxy arylamines. Aromatic amine derivatives, including the industrial intermediates acetoacetanilide, acetoacet-m-xylidide and N-ethylaniline, were examined for their ability to form Hb adducts in rats as potential biomarkers of exposure. The haemoglobin binding indices (HBI=binding [mmol mol^-1 Hb]/dose [mmol kg^-1 body weight]) of the arylamines were determined 24 h after oral administration to female Wistar rats. The precipitated haemoglobin was dissolved in 0.1 M sodium hydroxide in the presence of internal standards. After hexane extraction the released arylamines were analysed by gas chromatography-mass spectrometry (GC-MS). For aniline released from acetoacetanilide an HBI of 15 and for 2,4-dimethylaniline released from acetoacet-m-xylidide an HBI of 0.129 were determined. The HBIof aniline released from N-ethylaniline was 45.     

Discovery of benzotriazole-azo-phenol/aniline derivatives as antifungal agents

A series of benzotriazole-azo-phenol/aniline derivatives were prepared and evaluated for their antifungal activities against six phytopathogenic fungi such as Fusarium graminearum, Fusarium solani, Alternaria alternate, Valsa mali, Botrytis cinerea, and Curvularia lunata. Among them, compounds IIf, IIn, and IIr showed a broad-spectrum of potent antifungal activities. Especially some compounds displayed 3.5–10.8 folds more potent activities than carbendazim against A. alternata and C. lunata. Notably, compounds IIc, IIm, and IIr exhibited good protective and therapeutic effects against B. cinerea at 200?μg/mL. Their structure-activity relationships were also discussed.     

Genotoxicity and oxidative stress in fish after a short-term exposure to silver nanoparticles

This study examined the effects of waterborne silver nanoparticles (AgNPs) on juvenile fish Piaractus mesopotamicus (“pacú”), and analyzed toxicological endpoints such as metal burdens, oxidative stress and genotoxicity in a short-term assay. Fish were individually exposed to 0 (control), 2.5, 10, and 25 μg AgNPs/L. After 24 h, silver accumulation was greater in the brain than the liver and gills at all silver concentrations. Fish exposed to higher AgNPs concentrations showed major alterations in oxidative stress markers. An increase in lipid peroxidation (LPO) levels was observed in the liver of fish exposed to 10 μg AgNPs/L with no changes in the antioxidant enzymes activities. In the case of the 25 μg AgNPs/L treatment, a hepatic activation of the enzymatic antioxidant defense occurred, and LPO levels resulted unaltered. On the other hand, the brain presented the highest LPO levels at both 10 and 25 μg AgNPs/L exposures. The AgNPs toxicity was also evidenced by the DNA damage in fish erythrocytes at higher concentrations. Summarizing, a short exposure to sublethal concentrations of AgNPs is enough to generate deleterious effects on fish, including DNA damage.     

Utility of short-term tests for genetic toxicity

By definition, short-term tests (STTs) for genetic toxicity detect genotoxic agents, not carcinogens specifically. However, there is sufficient evidence, based on mechanistic considerations alone, to say that genotoxic agents are potential carcinogens. STTs have high statistical power, are almost always replicated, can be performed rather easily under various sets of experimental conditions, are relatively inexpensive, and detect a variety of endpoints relevant to carcinogenesis. In addition, several STTs have shown considerable utility in evaluating the genotoxic effects of real-world, environmental complex mixtures as well as the antimutagenic effects of various pure compounds and complex mixtures. STTs are likely to continue to be refined, resulting in STTs that are increasingly more relevant to human mutation and disease. Their utility should not be judged solely against the questionable standard of a rodent carcinogenicity assay.     

Lack of mutagenicity of diphenylhydantoin in in vitro short-term tests

The mutagenicity of diphenylhydantoin (DPH) and its major metabolite, 5-(p-hydroxyphenyl)-5-phenylhydantoin (HPPH), has been re-evaluated by the Ames test using Salmonella typhimurium and, for DPH only, by an in vitro cytogenetic test with human lymphocytes and a turbidimetric assay of tubulin polymerization. As negative results were obtained in all test systems used here, one has to conclude that DPH is devoid of mutagenic properties.     

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.