Mutagenic activity of heated potato/oil systems

Mutagens detected with Salmonella typhimurium strain TA 98 in the presence of liver S9 mix were extracted from potato slices, but not pure potato starch, after frying in oil. No mutagenic activity was detected using strain TA 100, in the presence or absence of S9 mix with either fried potato slices or potato starch. Mutagenic activity was detected at frying temperatures of 140 degrees C and above. The mutagenic activity was limited to the outer portion of the fried potato slices and increased with frying time and temperature. Mutagenic activity ratios for extraction with both (NH4)2SO4/NH4OH and Na2SO4/NaOH were similar.     

Air pollution survey in Kitakyushu district

Airborne particulate samples were collected on a glass fiber filter or quartz filter using Hi-volume air sampler from November, 1980 through February, 1983 at a west part of Yahata district, Japan. The concentrations of airborne particulates, polynuclear aromatic hydrocarbons (PAH), heavy metals and dustfall were determined, and mutagenic activities of tarry materials obtained from suspended particulates were also measured. The following results were obtained. (1) The airborne particulate contents were 22.1 - 188 mg/1000 m3 (mean : 74.6 mg/1000 m3), and the values were high in spring and low in summer. (2) PAH contents in airborne particulates were in the following order: benzo(ghi)perylene greater than benzo(a)pyrene greater than benz(a)anthracene greater than chrysene greater than benzo(k)fluoranthene greater than pyrene greater than perylene. PAH contents were higher in winter that in summer. The benzo(a)pyrene contents were 1.97 micrograms/1000 m3 in 1981 and 1.92 micrograms/1000 m3 in 1982. (3) Heavy metals content was about 2.1 - 3.6 higher in winter in comparison with that in summer time. (4) Mutagenic activity showed 90 - 11900 revertants/1000 m3 for TA 98 strain with S-9 mix and 50 - 7190 revertants/1000 m3 for TA 98 strain without S-9 mix. Mutagenic activities for TA 98 with S-9 mix were higher than those for TA 98 without S-9 mix. (5) As a result of the analysis of airborne particulate samples, a significant correlation was observed between mutagenic activities and the concentrations of PAH and heavy metals. These results indicated that the mutagenic survey may be useful as an index for air pollution study.     

Mutagenicity and antimutagenicity testing of six chemicals associated with the pungent properties of specific spices as revealed by the Ames Salmonella/microsomal assay

Three compounds, capsaicin, thymol and borneol, were initially screened for mutagenic activity using Salmonella typhimurium strains TA97, TA98 and TA100, with and without S9 metabolic activation, and 20 min standard preincubation time. Three other compounds, allyl isothiocyanate, eugenol and cinnamaldehyde, were screened for mutagenic activity as above, but with a prolonged, nonstandard preincubation time of up to 120 minutes. All six test compounds used in the assays are associated with the pungent properties of some specific spices in which the test compounds can be found to exist naturally. The first objective of this study was to observe if mutagenic activity can be correlated to the pungent properties of these six test compounds. However, due to toxicity and the observation that only capsaicin was mutagenic, using strain TA100 in the presence of S9 metabolic activation, it was not possible to deduce any relationship between mutagenicity and the test chemials' pungent properties. Naturally occurring capsaicin, found in the spice Capsicum annum, was detected and quantified using thin layer and gas chromatographic techniques.The final objective was to detect the presence of antimutagenic factor(s) in C. annum that would suppress the mutagenicity of capsaicin. When the mutagenic capsaicin and 2-aminoanthracene were assayed in the presence of C. annum acetone extract, using strain TA100 with S9 metabolic activation, the mutagenic response of both the mutagens were reduced by approximately 50%. Assaying capsaicin and 2-aminoanthracene in the presence of chlorophyll, the mutagenic response of the two mutagens was reduced by less than 40%. From this observation it was inferred that chlorophyll can successfully suppress the mutagenicity activities of capsaicin and 2-aminoanthracene, together with other antimutagenic factors that were present in the acetone extract of C. annum.     

Urinary screening for potentially genotoxic exposures in a chemical industry.

Mutagenic activity, measured by the bacterial fluctuation assay and thioether concentration in urine from workers at a chemical plant producing pharmaceuticals and explosives, was determined before and after exposure. Of 12 groups only those exposed to trinitrotoluene (n = 14) showed a significant increase in mutagenic activity using Salmonella typhimurium TA 98 without any exogenous metabolic system. The same strain responded only weakly when the S-9 mix was used; with Escherichia coli WP2 uvrA no effect of exposure was observed. Urinary thioether concentration was higher among smokers than among non-smokers, but occupational exposure had no effect. Urinary mutagenicity testing may be a useful tool for screening potentially genotoxic exposures in complex chemical environments.     

Fate of mutagenic activity during conventional treatment of municipal wastewater sludge

The mutagenic activity of wastewater was followed during conventional activated sludge treatment at a municipal plant. Raw wastewater was initially screened for mutagenic potential, using the AmesSalmonella/mammalian microsomal test and employer tester strains. The combined raw wastewater produced dose-related mutagenic responses in the presence of S9 metabolic activation. Raw wastewater from domestic sources alone was not mutagenic. Mutagenic activity was observed throughout the treatment process. Activated sludge prior to chlorination contained the highest specific mutagenic activity. Chlorination decreased the specific mutagenic activity at pH 11. Mutagenic activity in municipal wastewater containing industrial discharges is not removed by conventional treatment processes and can be enhanced by activated sludge treatment.     

Urinary screening for potentially genotoxic exposures in a chemical industry

Mutagenic activity, measured by the bacterial fluctuation assay and thioether concentration in urine from workers at a chemical plant producing pharmaceuticals and explosives, was determined before and after exposure. Of 12 groups only those exposed to trinitrotoluene (n = 14) showed a significant increase in mutagenic activity using Salmonella typhimurium TA 98 without any exogenous metabolic system. The same strain responded only weakly when the S-9 mix was used; with Escherichia coli WP2 uvrA no effect of exposure was observed. Urinary thioether concentration was higher among smokers than among non-smokers, but occupational exposure had no effect. Urinary mutagenicity testing may be a useful tool for screening potentially genotoxic exposures in complex chemical environments.     

Mutagenicity of aerosols from the oxidative thermal decomposition of rigid polyurethane foam

Summary The aerosol fraction of the oxidative thermal decomposition products (700°C) of rigid polyurethane foam was collected on glass fiber filters and fractionated into ether-soluble neutral, acidic, and basic fractions and water-soluble compounds. The fractions showed mutagenic activity in a bacterial fluctuation test with Salmonella typhimurium TA 98 or Escherichia coli CM 891 as the tester strains. All the fractions induced mutations in both strains after metabolic activation with rat liver S-9 mix. The basic and the water-soluble fractions were mutagenic for S. typhimurium TA 98 even without activation.Thin-layer chromatography showed the presence of several primary aromatic amines in the aerosol. Polycyclic aromatic hydrocarbons were not detected by glass capillary gas chromatography.We thank the Finnish Academy and the Swedish Work Environment Fund (Grant 241 C/77) for financial aid     

Mutagenicity and PAH Contents of Soil in Forests or Planted Areas in Japan

We investigated the behavior of mutagenic substances in the soil of forests or planted areas. Mutagenicity and concentration was examined for 16 types of PAHs in soil samples collected at a depth of 1 m in 10 forests in Iwate, Ibaraki, Tokyo, Kanagawa, Yamanashi and Shizuoka prefectures in Japan. Mutagenicity and PAHs were detected mostly in soil from the surface to a depth of 30 cm when strains TA100, TA98 and YG1024 were used. In addition, a significant correlation was not found between the concentration of BaP, and specific mutagenic activity (TA98 without S9mix, r = 0.285).     

Mutagenic activity of surface waters adjacent to a nuclear fuel processing facility

Surface waters adjacent to a nuclear fuel processing facility were extracted, using XAD-resin adsorption followed by solvent elution, and the extracts were assayed for mutagenic potential by the AmesSalmonella-mammalian microsome test. Dose-related mutagenic responses with TA102 (+ S9) were produced with the extracts of water samples obtained from a creek receiving waste-water from the processing facility (specific mutagenic activities of 7,250 to 8,250 net revertants per L equivalent of water). The creek water extracts were not mutagenic with TA102 in the absence of S9, or with any other tester strain (i.e., TA97, TA98, TA100, and TA1535) in the presence or absence of S9. Surface water samples downstream and upstream of this creek were not mutagenic; apparently indicating the lack of persistence of the observed mutagenicity. The major constituent in the mutagenic creek water extracts was identified as tributylphosphate (TBP) by gas chromatography-mass spectrometry. However, TBP was not mutagenic with TA102 (+ S9) at doses ranging from 196 g/plate to 9.8 ng/plate. Because tester strain TA102 detects oxidative mutagenesis due to x-rays and ultraviolet radiation, it is possible that the observed mutagenicity of creek water extracts was due to radionuclides complexed to TBP.     

Correlation of mutagenicity and tumorigenicity of betel quid and its ingredients

The mutagenic activity of betel quid and its ingredients was determined using Salmonella typhimurium tester strains TA 100, TA 1535, TA 98, and TA 1538, both in the presence and absence of S9 mixture. Aqueous extracts of betel quid (BQ), betel quid with tobacco (BQT), and betel nut (BN) were mutagenic in strain TA 100. Aqueous extract of betel leaf (BL) was not mutagenic in any of the four strains. Arecoline and arecaidine, which are major alkaloids present in BN, were mutagenic in all four tester strains.

Tumorigenicity studies in Swiss mice given the above constituents showed that BN and BQ induced lung tumors (47% and 26%, respectively). However, when BN was fed with BL, tumorigenicity was lowered to 38%. BL alone was not tumorigenic. Thus, the mutagenicity of betel quid and its ingredients is correlated with tumorigenicity.     

Validity of mutagenic activity as an indicator of river water pollution

Objectives To investigate if mutagenicity could be expressed by known water pollution indicators, we determined the mutagenic activity of blue rayon extracts from sampled river water with the Ames test utilizing new strains of bacteria, and compared the results with those of known indicators of water pollution. Methods Water samples were collected by the blue rayon adsorption method at sixteen sites in six rivers in the North Kyushu district. The Assay of mutagenicity was carried out using the Ames test. The test strains wereSalmonella typhimurium TA100, YG1024, YG1041 and YG1042. B(a)P, Trp-P-1 and Trp-P-2 were quantified by HPLC. Determinations of SS, BOD, COD, T-N, T-P, DOC, and A₂₆₀/DOC were performed. Results The extracts from five sampling sites showed higher mutagenicity toward strain YG1024 with or without S9mix, and the extracts from two of these five sites showed higher mutagenicity toward strain YG1041 with and without S9mix. However, the water pollution indicators did not show specific trends that were consistent with the mutagenic activity. Conclusions Since the mutagenic activity of river water could not be predicted using known water pollution indicators, we recommend that biological examinations such as mutagenicity tests be added to the indicators that are currently in use.     

Monitoring exposure of hospital personnel handling cytostatic drugs and contaminated materials

A study was undertaken to evaluate the urine mutagenicity of 63 individuals working in four hospital departments. The exposed group included 38 subjects who were exposed to various cytostatic drugs and/or contaminated material from treated patients. The control group included 25 individuals of the hospital personnel. Urine mutagenicity was monitored by the Ames test using tester strains TA 98 + S9 Mix and TA 102 — S9 Mix. Urine samples were collected before and after the working periods. A total of 29/116 (25%) urine samples were mutagenic for either strain. Among the mutagenic samples, 24/29 were mutagenic for tester strain TA 98 exclusively. No significant correlation could be found between occupational exposure to cytostatic drugs and urine mutagenicity evaluated by the strain TA 98 + S9 Mix. Smoking was the main environmental factor that modulated urine mutagenicity with TA 98. Three subjects in the exposed group had mutagenic urine samples at the end of the working period with strain TA 102 — S9 Mix. This mutagenicity was related to occupational exposure to cisplatin. In the control group, one individual had mutagenic samples before and after the working period. Assessing occupational exposure to cytostatic drugs with strain TA 102 requires additional studies to determine environmental mutagens which can be detected by this strain.     

The effect of rosemary on the mutagenic activity of heterocyclic amines extracted from common food consumed in Saudi Arabia

Meat intake may increase cancer risk as heterocyclic amines (HCAs) are one of the food mutagens produced in meat cooked at high temperature. The consumption of meat in Saudi Arabia is high compared with other developing countries and the incidence of cancer has been increasing during the past 30 years. The present study aimed to quantitatively determine the effect of rosemary on the mutagenic activity and the amount of HCAs formed in beef Shawerma, grilled chicken and fried liver as an attempt to minimize the carcinogenic risk of HCAs formed in these commonly consumed meat dishes. Surprisingly, rosemary extracts (2%, 5%, 10% and 15%) apparently enhanced the total amount of HCAs measured in beef Shawerma, whereas 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was the only mutagenic amine inhibited by 2% rosemary with a reduction up to 61.6% compared with control. In grilled chicken, the total amount of HCAs measured in 2% rosemary samples was reduced seven-fold lower than the control level, whereas PhIp and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (TrpP1) were inhibited to non-detectable levels. These data demonstrate that 2% rosemary may play an important role in attenuating the production of PhIP in both Shawerma and fried chicken. In fried liver, HCAs were not detected either in the control or in 2% treated samples whereas augmented levels of TrpP1 were measured in 5%, 10% and 15% rosemary. The mutagenic activity of HCAs extracted from all beef Shawerma and grilled chicken treated samples increased over the control sample using Salmonella typhimurium TA100. In fried liver, the mutagenic activity detected in the control sample was higher than treated samples, which suggests that S. typhimurium TA100 might be less sensitive in detecting the mutagenic response of TrpP1 extracted from the real food system. We believe more research is needed to assess the role of antioxidants in the formation of HCAs in order to optimize both safety and quality of our diets.     

Mutagenicity of rice-straw and -husk ashes by Ames test]

In the rice-producing district of Japan, environmental pollution by smoke from burnt rice straws has become a matter of concern. The mutagenicity of fly- and bottom-ashes of rice-straw and -husk was assayed by the Ames test, TA100 +/- S9 and TA98 +/- S9, and the relationship of combustion temperature to mutagenicity was investigated. Fly ash showed weak mutagenicity at 300 degrees C, with no remarkable change in mutagenic activity between 300 degrees C and 500 degrees C. Above 500 degrees C the mutagenic activity increased with a rise of temperature. The increasing rate of mutagenicity was much higher in the test system with S9 mix than that without S9. Moreover, the mutagenicity with TA100 was stronger than with TA98. With respect to bottom ash, weak mutagenic activity was observed at 300 degrees C, but at 400 degrees C decreased and at 500 degrees C or above could not be observed. Fly ash derived from burning 1 g of rice straw at 600 degrees C showed about 14 times and 2.5 times higher mutagenicity than main stream smoke condensates from the burning of 1 g of cigarette in TA100 + S9 and TA98 + S9 test systems respectively.     

Identification of genotoxic compounds used in leather processing industry

The release of mutagens from 7 carbon black-based leather dyes and from leather samples at various stages of finishing was determined. After vigorous treatment with toluene, 4 commercial dyes yelded mutagenic extracts on Salmonella typhimurium in the presence of microsomal enzymes. Only in one case were the responsible chemicals identified as polycyclic aromatic hydrocarbons. The low bioavailability of mutagens contained in carbon black and their low mutagenic activity suggest that the risk associated with the use of these dyes is probably negligible. Soxhlet extracts with ethanol from finished leather were mutagenic on strain TA98 of Salmonella typhimurium in the absence of S9 mix. Analysis of extracts of leather samples at various intermediate stages of processing showed that mutagenic activity was detectable after the colouring process. The responsible compound was identified as a nitroazo dye (Colour Index: Acid Brown 83), with a mutagenic potential of about 4 revertant/micrograms. Eighteen commercial tannins containing mainly Cr(III) sulphates were assessed for genotoxicity. Most were contaminated with Cr(VI), a known mutagenic and carcinogenic agent, at levels sufficient to induce an increased frequency of SCE (sister chromatid exchanges) in mammalian cells (CHO, chinese hamster ovary) tested in vitro.     

Handling of cytostatic drugs and urine mutagenesis

Summary As part of a French national epidemiologic study on human reproduction among hospital personnel, we investigated urine mutagenicity of nurses and personnel from oncology units exposed to cytostatic drugs. During a first series of experiments, urine mutagenicity of 47 subjects working in six oncology units was investigated in the Marseille regional's hospital. A control group of 37 individuals working in one cardiology clinic was also included. Urinary mutagens were extracted on XAD-2 resin and tested by two bacterial mutagenicity tests: the Ames test with tester strains Salmonella typhimurium TA 97, TA 98, TA 100 and TA 102 with or without metabolic activation (S9 MIX) and the SOS Chromotest with tester strain Escherichia coli PQ 37-S9 MIX. Bactericidal activity towards the tester strains was found in 40% of the urine samples (36/90). During a second series of experiments, urine mutagenicity of 17 office clerks was also investigated. Toxicity was found in six of the 21 urine samples. No significant difference of toxicity distribution and no relationship between toxicity and cigarette smoking were found. Qualitative analysis of the data showed no significant difference among the exposed groups and the control group (Chi 2 = 0.529, df = 2) with tester strain TA 98 + S9 MIX. Cigarette smoking was found to be the main factor of increased urinary mutagenicity (Chi 2 = 0.529, df = 1). Quantitative analysis of the data showed that mutagenic potencies varied from 0.332 ±0.539 revertants/mg creatinine to 7.226 ± 6.743 revertants/mg creatinine with TA 98 + S9 MIX. A relationship between the number of cigarettes smoked and mutagenic potency was found (Spearman rank coefficient r _s = 0.412, P < 0.05). One urine sample was found to be mutagenic with tester strain TA 102 and PQ 37.     

应用菌株YG1024对吸烟者尿致突变性的研究

应用鼠伤寒沙门氏菌株ＴＡ９８及其富含硝基还原酶的衍生菌株ＹＧ１０２１和富含０－乙酰转移酶的衍生菌株ＹＧ１０２４检测了吸烟者尿的致突变性。结果表明，在有鼠肝Ｓ９存在时吸烟者尿样对菌株ＹＧ１０２４的致突变作用明显高于ＴＡ９８，而相同条件下菌株ＹＧ１０２１的回变性与ＴＡ９８大致相同。证明菌株ＹＧ１０２４在检测吸烟者尿致突变性上比传统的＂敏感＂菌株ＴＡ９８更为敏感。同时也提示吸烟者尿中的致突变物主要是芳香胺类物质。     

Mutagenicity studies and D-glucaric acid determination in urine of workers exposed to mineral oils

Summary Urine from workers of a cold-rolling steel plant exposed to mineral oils were tested for the mutagenic activity by the Salmonella/microsome assay, and for D-glucaric acid content as a measure of hepatic mixed-function oxidase activity. An occupationally unexposed group served as control. The biological monitoring phase followed an environmental phase carried out in the working environment that showed a substantially low mutagenic/carcinogenic risk for the exposed workers. Urine samples were collected before, during and after work. From the results it was observed that the urinary mutagenicity was detectable only with TA98 strain in the presence of enzymatic activation (+ S9 mix). Further addition of beta-glucuronidase did not give any enhanced mutagenic effects. There was a significant difference in urinary mutagenicity between the exposed and control workers. However, in both groups the highest mutagenicity data was found in smokers: both exposed smoking workers and smoking controls had significantly higher urine mutagenicity than the non-smoking exposed and control workers. The results suggested a synergistic effect of smoking with exposure to mineral oils: the mutagenicity of urine from exposed smokers was significantly higher than that of control smokers. There was no difference in urinary D-glucaric acid results between exposed and unexposed groups, however, smokers of both groups had a significant increase in D-glucaric acid excretion. The authors suggest that even for this workplace with its low mutagenic/carcinogenic risk, smoking could interact with the complex mixtures present in the environment, and thus modify urinary mutagenicity data.     

Genotoxic and Mutagenic Potential of Agricultural Soil Irrigated with Tannery Effluents at Jajmau (Kanpur), India

It is a common practice in India to irrigate agricultural fields with wastewater originating from industries and domestic sources. At Jajmau (Kanpur), India, tannery effluent is used for irrigation purposes. This practice has been polluting the soil directly and groundwater and food crops indirectly. This study is aimed at evaluating the mutagenic impact of soil irrigated with tannery effluent. Soil extracts were prepared using four organic solvents (dichloromethane, methanol, acetonitrile, and acetone) and tested with Ames Salmonella/microsome test and DNA repair-defective E. coli k-12 mutants. Gas Chromatography-mass spectrometric analysis of soil samples revealed the presence of a large number of organic compounds including bis(2-ethylhexyl)phthalate, benzene, 1,3-hexadien-5-yne, 2,4-bis(1,1-dimethyl)phenol, Docosane, 10-methylnonadecane, and many higher alkanes. The soil extracts exhibited significant mutagenicity with Ames tester strains. TA98 was found to be the most sensitive strains to all the soil extracts, producing maximum response in terms of mutagenic index of 14.2 (–S9) and 13.6 (+S9) in the presence of dichloromethane extract. Dichloromethane-extracted soil exhibited a maximum mutagenic potential of 17.3 (–S9) and 20.0 (+S9) revertants/mg soil equivalent in TA100. Methanol, acetonitrile, and acetone extracts were also found to be mutagenic. A significant decline in the survival of DNA repair-defective E. coli K-12 mutants was observed compared to their isogenic wild-type counterparts when treated with different soil extracts. PolA mutant was found to be the most sensitive strain toward all four soil extracts.     

Correlation of mutagenicity and tumorigenicity of betel quid and its ingredients

The mutagenic activity of betel quid and its ingredients was determined using Salmonella typhimurium tester strains TA 100, TA 1535, TA 98, and TA 1538, both in the presence and absence of S9 mixture. Aqueous extracts of betel quid (BQ), betel quid with tobacco (BQT), and betel nut (BN) were mutagenic in strain TA 100. Aqueous extract of betel leaf (BL) was not mutagenic in any of the four strains. Arecoline and arecaidine, which are major alkaloids present in BN, were mutagenic in all four tester strains. Tumorigenicity studies in Swiss mice given the above constituents showed that BN and BQ induced lung tumors (47% and 26%, respectively). However, when BN was fed with BL, tumorigenicity was lowered to 38%. BL alone was not tumorigenic. Thus, the mutagenicity of betel quid and its ingredients is correlated with tumorigenicity.