mutagenic problems posed: Topics by Science.gov

Sample records for mutagenic problems posed

Carbamates and ICH M7 classification: Making use of expert knowledge.

PubMed

Hemingway, Rachel; Fowkes, Adrian; Williams, Richard V

2017-06-01

Carbamates are widely used in the chemical industry so understanding their toxicity is important to safety assessment. Carbamates have been associated with certain toxicities resulting in publication of structural alerts, including alerts for mutagenicity. Structural alerts for bacterial mutagenicity can be used in combination with statistical systems to enable ICH M7 classification, which allows assessment of the genotoxic risk posed by pharmaceutical impurities. This study tested a hypothetical bacterial mutagenicity alert for carbamates and examined the impact it would have on ICH M7 classifications using (Q)SAR predictions from the expert rule-based system Derek Nexus and the statistical-based system Sarah Nexus. Public datasets have a low prevalence of mutagenic carbamates, which highlighted that systems containing an alert for carbamates perform poorly for achieving correct ICH M7 classifications. Carbamates are commonly used as protecting groups and proprietary datasets containing such compounds were also found to have a low prevalence of mutagenic compounds. Expert review of the mutagenic compounds established that mutagenicity was often only observed under certain (non-standard) conditions and more generally that the Ames test may be a poor predictor for the risk of carcinogenicity posed by chemicals in this class. Overall a structural alert for the in vitro bacterial mutagenesis of carbamates does not benefit workflows for assigning ICH M7 classification to impurities. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.
AN EVALUATION OF THE MUTAGENICITY, METABOLISM AND DNA ADDUCT FORMATION OF 5-NITROBENZO[B]NAPHTHO[2,1-D]THIOPHENE

EPA Science Inventory

An Evaluation of the Mutagenicity, Metabolism and DNA Adduct Formation of 5-Nitrobenzo[b ]naphtho[2, I-d]thiophene

Thioarenes, sulfur containing polycyclic aromatic compounds, are environmental contaminants suspected of posing human health risks. In this study, 5-nitroben...
Combined Biological and Chemical Mechanisms for Degradation of Insensitive Munitions in the Presence of Alternate Explosives

DTIC Science & Technology

2017-06-21

military facilities and firing ranges, may pose a risk to the environment10 and humans ’ health .13 As such, it may require a remediation plan for the...fire ranges. Nitroaromatic and nitramine compounds such as explosives are carcinogenic and mutagenic so they pose threat to human health and the...detonations. It is crucial to understand their fate and transport in subsurface environments as they can pose a significant hazard to humans and
Novel naïve Bayes classification models for predicting the chemical Ames mutagenicity.

PubMed

Zhang, Hui; Kang, Yan-Li; Zhu, Yuan-Yuan; Zhao, Kai-Xia; Liang, Jun-Yu; Ding, Lan; Zhang, Teng-Guo; Zhang, Ji

2017-06-01

Prediction of drug candidates for mutagenicity is a regulatory requirement since mutagenic compounds could pose a toxic risk to humans. The aim of this investigation was to develop a novel prediction model of mutagenicity by using a naïve Bayes classifier. The established model was validated by the internal 5-fold cross validation and external test sets. For comparison, the recursive partitioning classifier prediction model was also established and other various reported prediction models of mutagenicity were collected. Among these methods, the prediction performance of naïve Bayes classifier established here displayed very well and stable, which yielded average overall prediction accuracies for the internal 5-fold cross validation of the training set and external test set I set were 89.1±0.4% and 77.3±1.5%, respectively. The concordance of the external test set II with 446 marketed drugs was 90.9±0.3%. In addition, four simple molecular descriptors (e.g., Apol, No. of H donors, Num-Rings and Wiener) related to mutagenicity and five representative substructures of mutagens (e.g., aromatic nitro, hydroxyl amine, nitroso, aromatic amine and N-methyl-N-methylenemethanaminum) produced by ECFP_14 fingerprints were identified. We hope the established naïve Bayes prediction model can be applied to risk assessment processes; and the obtained important information of mutagenic chemicals can guide the design of chemical libraries for hit and lead optimization. Copyright © 2017 Elsevier B.V. All rights reserved.
QSAR models to predict mutagenicity of acrylates, methacrylates and alpha,beta-unsaturated carbonyl compounds.

PubMed

Pérez-Garrido, Alfonso; Helguera, Aliuska Morales; Rodríguez, Francisco Girón; Cordeiro, M Natália D S

2010-05-01

The purpose of this study is to develop a quantitative structure-activity relationship (QSAR) model that can distinguish mutagenic from non-mutagenic species with alpha,beta-unsaturated carbonyl moiety using two endpoints for this activity - Ames test and mammalian cell gene mutation test - and also to gather information about the molecular features that most contribute to eliminate the mutagenic effects of these chemicals. Two data sets were used for modeling the two mutagenicity endpoints: (1) Ames test and (2) mammalian cells mutagenesis. The first one comprised 220 molecules, while the second one 48 substances, ranging from acrylates, methacrylates to alpha,beta-unsaturated carbonyl compounds. The QSAR models were developed by applying linear discriminant analysis (LDA) along with different sets of descriptors computed using the DRAGON software. For both endpoints, there was a concordance of 89% in the prediction and 97% confidentiality by combining the three models for the Ames test mutagenicity. We have also identified several structural alerts to assist the design of new monomers. These individual models and especially their combination are attractive from the point of view of molecular modeling and could be used for the prediction and design of new monomers that do not pose a human health risk. 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
Reduction of hexavalent chromium by fasted and fed human gastric fluid. I. Chemical reduction and mitigation of mutagenicity.

PubMed

De Flora, Silvio; Camoirano, Anna; Micale, Rosanna T; La Maestra, Sebastiano; Savarino, Vincenzo; Zentilin, Patrizia; Marabotto, Elisa; Suh, Mina; Proctor, Deborah M

2016-09-01

Evaluation of the reducing capacity of human gastric fluid from healthy individuals, under fasted and fed conditions, is critical for assessing the cancer hazard posed by ingested hexavalent chromium [Cr(VI)] and for developing quantitative physiologically-based pharmacokinetic models used in risk assessment. In the present study, the patterns of Cr(VI) reduction were evaluated in 16 paired pre- and post-meal gastric fluid samples collected from 8 healthy volunteers. Human gastric fluid was effective both in reducing Cr(VI), as measured by using the s-diphenylcarbazide colorimetric method, and in attenuating mutagenicity in the Ames test. The mean (±SE) Cr(VI)-reducing ability of post-meal samples (20.4±2.6μgCr(VI)/mL gastric fluid) was significantly higher than that of pre-meal samples (10.2±2.3μgCr(VI)/mL gastric fluid). When using the mutagenicity assay, the decrease of mutagenicity produced by pre-meal and post-meal samples corresponded to reduction of 13.3±1.9 and 25.6±2.8μgCr(VI)/mL gastric fluid, respectively. These data are comparable to parallel results conducted by using speciated isotope dilution mass spectrometry. Cr(VI) reduction was rapid, with >70% of total reduction occurring within 1min and 98% of reduction is achieved within 30min with post-meal gastric fluid at pH2.0. pH dependence was observed with decreasing Cr(VI) reducing capacity at higher pH. Attenuation of the mutagenic response is consistent with the lack of DNA damage observed in the gastrointestinal tract of rodents following administration of ≤180ppm Cr(VI) for up to 90days in drinking water. Quantifying Cr(VI) reduction kinetics in the human gastrointestinal tract is necessary for assessing the potential hazards posed by Cr(VI) in drinking water. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.
Caffeine enhanced measurement of mutagenesis by low levels of [gamma]-irradiation in human lymphocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puck, T.P.; Johnson, R.; Waldren, C.A.

1993-09-01

The well-known action of caffeine in synergizing mutagenesis (including chromosome aberrations) of agents like ionizing radiation by inhibition of cellular repair processes has been incorporated into a rapid procedure for detection of mutagenicity with high sensitivity. Effects of 5-10 rads of [gamma]-irradiation, which approximate the human lifetime dose accumulation from background radiation, can be detected in a two-day procedure using an immortalized human WBC culture. Chromosomally visible lesions are scored on cells incubated for 2 h after irradiation in the presence and absence of 1.0 mg/ml of caffeine. An eightfold amplification of scorable lesions is achieved over the action ofmore » radiation alone. This approach provides a closer approximation to absolute mutagenicity unmitigated by repair processes, which can vary in different situations. It is proposed that mutagenesis testing of this kind, using caffiene or other repair-inhibitory agents, be employed to identify mutagens in their effective concentrations to which human populations may be exposed; to detect agents such as caffeine that may synergize mutagenic actions and pose epidemiologic threats; and to discover effective anti-mutagens. Information derived from the use of such procedures may help prevent cancer and newly acquired genetic disease.« less
78 FR 22269 - International Conference on Harmonisation; Draft Guidance on M7 Assessment and Control of DNA...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-15

...The Food and Drug Administration (FDA) is announcing the availability of a draft guidance entitled ``M7 Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals to Limit Potential Carcinogenic Risk.'' The draft guidance was prepared under the auspices of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH). The draft guidance emphasizes considerations of both safety and quality risk management in establishing levels of mutagenic impurities that are expected to pose negligible carcinogenic risk. It outlines recommendations for assessment and control of mutagenic impurities that reside or are reasonably expected to reside in a final drug substance or product, taking into consideration the intended conditions of human use. The draft guidance is intended to provide guidance for new drug substances and new drug products during their clinical development and subsequent applications for marketing.
Reduction of hexavalent chromium by fasted and fed human gastric fluid. I. Chemical reduction and mitigation of mutagenicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Flora, Silvio, E-mail: sdf@unige.it

Evaluation of the reducing capacity of human gastric fluid from healthy individuals, under fasted and fed conditions, is critical for assessing the cancer hazard posed by ingested hexavalent chromium [Cr(VI)] and for developing quantitative physiologically-based pharmacokinetic models used in risk assessment. In the present study, the patterns of Cr(VI) reduction were evaluated in 16 paired pre- and post-meal gastric fluid samples collected from 8 healthy volunteers. Human gastric fluid was effective both in reducing Cr(VI), as measured by using the s-diphenylcarbazide colorimetric method, and in attenuating mutagenicity in the Ames test. The mean (± SE) Cr(VI)-reducing ability of post-meal samplesmore » (20.4 ± 2.6 μg Cr(VI)/mL gastric fluid) was significantly higher than that of pre-meal samples (10.2 ± 2.3 μg Cr(VI)/mL gastric fluid). When using the mutagenicity assay, the decrease of mutagenicity produced by pre-meal and post-meal samples corresponded to reduction of 13.3 ± 1.9 and 25.6 ± 2.8 μg Cr(VI)/mL gastric fluid, respectively. These data are comparable to parallel results conducted by using speciated isotope dilution mass spectrometry. Cr(VI) reduction was rapid, with > 70% of total reduction occurring within 1 min and 98% of reduction is achieved within 30 min with post-meal gastric fluid at pH 2.0. pH dependence was observed with decreasing Cr(VI) reducing capacity at higher pH. Attenuation of the mutagenic response is consistent with the lack of DNA damage observed in the gastrointestinal tract of rodents following administration of ≤ 180 ppm Cr(VI) for up to 90 days in drinking water. Quantifying Cr(VI) reduction kinetics in the human gastrointestinal tract is necessary for assessing the potential hazards posed by Cr(VI) in drinking water. - Highlights: • Cr(VI) reduction capacity was greater in post-meal than paired pre-meal samples. • Cr(VI) reduction was rapid, pH dependent, and due to heat stable components. • Gastric fluid attenuates the mutagenicity of Cr(VI) and reduces risk of GI cancer. • The results are useful to quantitatively evaluate the fate of ingested Cr(VI).« less
Development and Application of a Human PBPK Model for Bromodichloromethane (BDCM) to Investigate Impacts of Multi-Route Exposure

EPA Science Inventory

Due to its presence in water as a volatile disinfection byproduct, BDCM, which is mutagenic and a rodent carcinogen, poses a risk for exposure via multiple routes. We developed a refined human PBPK model for BDCM (including new chemical-specific human parameters) to evaluate the...
Use of a Salmonella microsuspension bioassay to detect the mutagenicity of munitions compounds at low concentrations.

PubMed

George, S E; Huggins-Clark, G; Brooks, L R

2001-01-25

Past production and handling of munitions has resulted in soil contamination at various military facilities. Depending on the concentrations present, these soils pose both a reactivity and toxicity hazard and the potential for groundwater contamination. Many munitions-related chemicals have been examined for mutagenicity in the Ames test, but because the metabolites may be present in low environmental concentrations, a more sensitive method is needed to elucidate the associated mutagenicity. RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), TNT (2,4,6-trinitrotoluene), tetryl (N-methyl-N-2,4,6-tetranitroaniline), TNB (1,3,5-trinitrobenzene) and metabolites were examined for mutagenicity in a microsuspension modification of the Salmonella histidine reversion assay with and without metabolic activation. TNB and tetryl were positive in TA98 (32.5, 5.2revertants/nmole) and TA100 (7.4, 9.5revertants/nmole) without metabolic activation and were more potent than TNT (TA98, 0.3revertants/nmole; TA100, 2.4revertants/nmole). With the exception of the tetranitroazoxytoluene derivatives, TNT metabolites were less mutagenic than TNT. RDX and two metabolites were negative in both strains, however, hexahydro-1,3,5-trinitroso-1,3,5-triazine was positive in TA100 with and without S9. Microsuspension bioassay results tend to correlate well with published Ames test data, however, there are discrepancies among the published data sets and the microsuspension assay results.
MUTAGENICITY OF TEFLON-COATED GLASS FIBER FILTERS: A POTENTIAL PROBLEM AND SOLUTIONS

EPA Science Inventory

Teflon-coated glass fiber filters, used in studies of airborne particulate matter, were tested for mutagenic activity using the Salmonella/mammalian-microsome (Ames) assay. For each sample, eight blank filters were simultaneously extracted with dichloromethane (DCM), and the extr...
Mutagenic substances in pyrolysate obtained by burning polyvinylchloride-product at 1000 degrees C.

PubMed

Yonezawa, Y; Saigusa, S; Takahagi, M; Nishioka, H

1999-06-25

In order to detect possible mutagenic substances in pyrolysate obtained by burning polyvinyl chloride product (PVC-P) at approximately 1000 degrees C, mutagenicity of rough extracts obtained by extraction with various solvents for the products was investigated by means of reversion mutation assay using Salmonella typhimurium TA98 and TA100 with or without microsomal metabolic activation (S9 mix). Strong mutagenicity in TA98 without S9 mix was observed in acetone-extract of PVC-P. The extract was fractionated into acidic, neutral and basic by liquid-liquid distribution and the mutagenicity in TA98 without S9 mix was found in the neutral fraction. Identification of mutagenic substances in the neutral fraction from acetone extract, which showed the strongest mutagenicity, was attempted by means of thin layer chromatography and capillary gas chromatography. The results suggest that mutagenic substances from pyrolysate of PVC-P are benzanthrone and an isomer of benzo(c)cinnoline. The results also suggest that burning wastes containing plastic products is not always safe even if at 1000 degrees C and further research on the problem is necessary. Copyright 1999 Elsevier Science B.V.
INFLUENCE OF CHEMICAL AND PHYSICAL MUTAGENIC FACTORS ON THE VIRUS of tick-BORNE ENCEPHALITIS

DTIC Science & Technology

In experiments the chemicals azouridine, azouracil, 5-bromuracil, formaldehyde, urethan and proflavine were used as mutagenic agents. The influence of...with passaging (tests with proflavine ). Subject to further study is the problem of the reversibility of these properties, and also the fixing of
Interrelationships among carcinogenicity, mutagenicity, acute toxicity, and chemical structure in a genotoxicity data base

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benigni, R.; Andreoli, C.; Giuliani, A.

1989-01-01

The interrelationships among carcinogenicity, mutagenicity, acute toxicity (LD50), and a number of molecular descriptors were studied by computerized data analysis methods on the data base generated by the International Program for the Evaluation of Short-Term Test for Carcinogens (IPESTTC). With the use of statistical regression methods, three main associations were evidenced: (1) the well-known correlation between carcinogenicity and mutagenicity; (2) a correlation between mutagenicity and toxicity (LD50 ip in mice); and (3) a correlation between toxicity and a recently introduced estimator of the free energy of binding of the molecules to biological receptors. As expected on the basis of themore » large variety of chemical classes represented in the IPESTTC data base, no simple relationship between mutagenicity or carcinogenicity and chemical descriptors was found. To overcome this problem, a new pattern recognition method (REPAD), developed by us for structure-activity studies of noncongeneric chemicals, has been used. This allowed us to highlight a significant difference between the whole patterns of relationships among chemicophysical variables in the two groups to active (mutagenicity and/or carcinogenic) and inactive chemicals. This approach generated a classification rule able to correctly assign about 80% of carcinogens or mutagens.« less
Use of biological assay systems to assess the relative carcinogenic hazards of disinfection by-products.

PubMed Central

Bull, R J; Robinson, M; Meier, J R; Stober, J

1982-01-01

Other workers have clearly shown that most, if not all, drinking water in the U.S. contains chemicals that possess mutagenic and/or carcinogenic activity by using bacterial and in vitro methods. In the present work, increased numbers of tumors were observed with samples of organic material isolated from 5 U.S. cities administered as tumor initiators in mouse skin initiation/promotion studies. Only in one case was the result significantly different from control. In studies designed to test whether disinfection practice contributes significantly to the tumor initiating activity found in drinking water mixed results have been obtained. In one experiment, water disinfected by chlorination, ozonation or combined chlorine resulted in a significantly greater number of papillomas when compared to nondisinfected water. In two subsequent experiments, where water was obtained from the Ohio River at different times of the year, no evidence of increased initiating activity was observed with any disinfectant. Analysis of water obtained at the comparable times of the year for total organic halogen, and trihalomethane formation revealed a substantial variation in the formation of these products. Considering the problems such variability poses for estimating risks associated with disinfection by-products, a model system which makes use of commercially obtained humic acid as a substrate for chlorination was investigated using the Ames test. Humic and fulvic acids obtained from two surface waters as well as the commercially obtained humic acid were without activity in TA 1535, TA 1537, TA 1538, TA 98 or TA 100 strains of S. typhimurium. Following treatment with a 0.8 molar ratio of chlorine (based on carbon) significant mutagenic activity was observed with all humic and fulvic acid samples. Comparisons of the specific mutagenic activity of the chlorinated products suggests that the commercial material might provide a useful model for studying health hazards associated with disinfection reactions by-products. PMID:7151763
Formation and fate of gaseous and particulate mutagens and carcinogens in real and simulated atmospheres.

PubMed Central

Pitts, J N

1983-01-01

The growing use of coal for heating and electric power generation and diesel engines in light duty motor vehicles will increase not only the existing atmospheric concentrations of criteria pollutants such as NO2, SO2, O3 and fine particulates, but also the concentrations of a number of highly reactive gaseous copollutants such as HONO, HONO2, PAN and the nitrate radical, NO3. These gaseous noncriteria pollutants are of interest not only because of their roles in the chemistry of the "clean" and polluted troposphere, including "acid rain," but also because they may pose health risks disproportionate to their relatively low ambient concentrations, and through complex heterogeneous reactions, they may serve as precursors or catalysts in the formation of "nonclassical" particulate mutagens and carcinogens such as certain nitroarenes associated with combustion generated particulate polycyclic organic matter (POM). Results of research efforts to establish current ambient levels of these noncriteria pollutants and to develop an understanding of their sources, formation and sinks are reported here. First, long pathlength (greater than or equal to 1 km) infrared and UV-visible spectroscopic studies of ambient levels of gaseous HONO, NO3, HONO2, PAN, HCHO and HCOOH in southern California atmospheres are described, and data given on their ambient concentrations. Second, an integrated chemical/microbiological investigation is described. It is directed toward identifying the nature of direct-acting mutagens found in extracts of diesel and ambient POM, as well as those formed upon exposure of environmentally relevant PAH to simulated natural and polluted atmospheres. The identification of certain of these mutagens, including a newly identified class of mutagenic PAH-lactones is discussed, along with the mechanisms of their formation and fate in the natural and polluted troposphere. PMID:6337822
A site-directed mutagenesis method particularly useful for creating otherwise difficult-to-make mutants and alanine scanning.

PubMed

Wan, Haisu; Li, Yongwen; Fan, Yu; Meng, Fanrong; Chen, Chen; Zhou, Qinghua

2012-01-15

Site-directed mutagenesis has become routine in molecular biology. However, many mutants can still be very difficult to create. Complicated chimerical mutations, tandem repeats, inverted sequences, GC-rich regions, and/or heavy secondary structures can cause inefficient or incorrect binding of the mutagenic primer to the target sequence and affect the subsequent amplification. In theory, these problems can be avoided by introducing the mutations into the target sequence using mutagenic fragments and so removing the need for primer-template annealing. The cassette mutagenesis uses the mutagenic fragment in its protocol; however, in most cases it needs to perform two rounds of mutagenic primer-based mutagenesis to introduce suitable restriction enzyme sites into templates and is not suitable for routine mutagenesis. Here we describe a highly efficient method in which the template except the region to be mutated is amplified by polymerase chain reaction (PCR) and the type IIs restriction enzyme-digested PCR product is directly ligated with the mutagenic fragment. Our method requires no assistance of mutagenic primers. We have used this method to create various types of difficult-to-make mutants with mutagenic frequencies of nearly 100%. Our protocol has many advantages over the prevalent QuikChange method and is a valuable tool for studies on gene structure and function. Copyright © 2011 Elsevier Inc. All rights reserved.
Health hazards associated with the use of di-(2-ethylhexyl) phthalate (commonly referred to as DOP) in HEPA filter test

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-01-01

Di-(2-ethylhexyl) phthalate (DEHP), commonly referred to as di-octyl phthalate, is an important production chemical in the US. In addition to its major use as an additive in plastics, DEHP is widely used to evaluate the effectiveness of high efficiency particulate air (HEPA) filters. Historically, DEHP was also used in quantitative fit testing for respirators. Evaluations of this compound a decade ago showed that it can induce hepatocellular carcinomas in laboratory animals. Although most Department of Energy (DOE) facilities have since discontinued using DEHP in respirator fit testing, DEHP continues to be used for evaluating HEPA filters. This report summarizes availablemore » information on the toxicity, mutagenicity, carcinogenicity, and other hazards and problems posed by DEHP, specifically with reference to HEPA filter testing. Information on work practice improvements as well as the availability and suitability of DEHP substitutes are also presented. This material should assist the DOE in the safe use of this material.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)

Wyrobek, Andrew J.; Mulvihill, John J.; Wassom, John S.

Although numerous germ-cell mutagens have been identified inanimal model systems, to date, no human germ-cell mutagens have beenconfirmed. Because the genomic integrity of our germ cells is essentialfor the continuation of the human species, a resolution of this enduringconundrum is needed. To facilitate such a resolution, we organized aworkshop at The Jackson Laboratory in Bar Harbor, Maine on September28-30, 2004. This interactive workshop brought together scientists from awide range of disciplines to assess the applicability of emergingmolecular methods for genomic analysis to the field of human germ-cellmutagenesis. Participants recommended that focused, coordinated humangerm-cell mutation studies be conducted in relation tomore » important societalexposures. Because cancer survivors represent a unique cohort withwell-defined exposures, there was a consensus that studies should bedesigned to assess the mutational impact on children born to parents whohad received certain types of mutagenic cancer chemotherapy prior toconceiving their children. Within this high-risk cohort, parents andchildren could be evaluated for inherited changes in (a) gene sequencesand chromosomal structure, (b) repeat sequences and minisatelliteregions, and (c) global gene expression and chromatin. Participants alsorecommended studies to examine trans-generational effects in humansinvolving mechanisms such as changes in imprinting and methylationpatterns, expansion of nucleotide repeats, or induction of mitochondrialDNA mutations. Workshop participants advocated establishment of abio-bank of human tissue samples that could be used to conduct amultiple-endpoint, comprehensive, and collaborative effort to detectexposure-induced heritable alterations in the human genome. Appropriateanimal models of human germ-cell mutagenes is should be used in parallelwith human studies to provide insights into the mechanisms of mammaliangerm-cell mutagenesis. Finally, participants recommended that scientificspecialty groups be convened to address specific questions regarding thepotential germ-cell mutagenicity of environmental, occupational, andlifestyle exposures. Strong support from relevant funding agencies andengagement of scientists outside the fields of genomics and germ-cellmutagenesis will be required to launch a full-scale assault on some ofthe most pressing and enduring questions in environmental mutagenesis: Dohuman germ-cell mutagens exist, what risk do they pose to futuregenerations, and are some parents at higher risk than others foracquiring and transmitting germ-cell mutations?« less

The Relationship between Students' Problem Posing and Problem Solving Abilities and Beliefs: A Small-Scale Study with Chinese Elementary School Children

ERIC Educational Resources Information Center

Limin, Chen; Van Dooren, Wim; Verschaffel, Lieven

2013-01-01

The goal of the present study is to investigate the relationship between pupils' problem posing and problem solving abilities, their beliefs about problem posing and problem solving, and their general mathematics abilities, in a Chinese context. Five instruments, i.e., a problem posing test, a problem solving test, a problem posing questionnaire,…
Pre-Service Teachers' Free and Structured Mathematical Problem Posing

ERIC Educational Resources Information Center

Silber, Steven; Cai, Jinfa

2017-01-01

This exploratory study examined how pre-service teachers (PSTs) pose mathematical problems for free and structured mathematical problem-posing conditions. It was hypothesized that PSTs would pose more complex mathematical problems under structured posing conditions, with increasing levels of complexity, than PSTs would pose under free posing…
Influence of ozonation on the in vitro mutagenic and toxic potential of secondary effluents.

PubMed

Petala, M; Samaras, P; Zouboulis, A; Kungolos, A; Sakellaropoulos, G P

2008-12-01

Reclamation of municipal effluents by advanced treatment processes is an attractive perspective for facing certain water shortage problems. However, the application of tertiary techniques should be thoroughly examined for their potential hazardous effects. Ozonation is an efficient chemical oxidation method, often used in wastewater reclamation, which may result in by-products that may alter the toxic and mutagenic properties of effluents. In this study, Ames test and Microtox test were used for the evaluation of ozonation efficiency to upgrade secondary effluents quality. In general, the toxic response and mutagenic effect without metabolic activation of test species were influenced mainly by the ozone dose and ozonation duration, whereas the mutagenic effect with metabolic activation was influenced mainly by ozone dose, indicating that ozone conditions strongly affect the formation of by-products. In most cases, the toxicity was increased and reached up to 100% (in relation to that of secondary effluent) after ozonation with 8.0 mg O3/L for 5 min. On the contrary, in most cases the mutagenic activity towards strain TA98 without metabolic activation was reduced, when ozone dose and contact time increased. However, the mutagenicity was also increased after ozonation at low ozone doses and for contact times less than 5 min. The mutagenic activity of treated effluents towards strain TA98 with metabolic activation remained about the same or was reduced, compared to that of secondary effluent, and was even eliminated after ozonation with 8.0 mg O3/L for contact times higher than 5 min.
Creativity of Field-dependent and Field-independent Students in Posing Mathematical Problems

NASA Astrophysics Data System (ADS)

Azlina, N.; Amin, S. M.; Lukito, A.

2018-01-01

This study aims at describing the creativity of elementary school students with different cognitive styles in mathematical problem-posing. The posed problems were assessed based on three components of creativity, namely fluency, flexibility, and novelty. The free-type problem posing was used in this study. This study is a descriptive research with qualitative approach. Data collections were conducted through written task and task-based interviews. The subjects were two elementary students. One of them is Field Dependent (FD) and the other is Field Independent (FI) which were measured by GEFT (Group Embedded Figures Test). Further, the data were analyzed based on creativity components. The results show thatFD student’s posed problems have fulfilled the two components of creativity namely fluency, in which the subject posed at least 3 mathematical problems, and flexibility, in whichthe subject posed problems with at least 3 different categories/ideas. Meanwhile,FI student’s posed problems have fulfilled all three components of creativity, namely fluency, in which thesubject posed at least 3 mathematical problems, flexibility, in which thesubject posed problems with at least 3 different categories/ideas, and novelty, in which the subject posed problems that are purely the result of her own ideas and different from problems they have known.
Skill Levels of Prospective Physics Teachers on Problem Posing

ERIC Educational Resources Information Center

Cildir, Sema; Sezen, Nazan

2011-01-01

Problem posing is one of the topics which the educators thoroughly accentuate. Problem posing skill is defined as an introvert activity of a student's learning. In this study, skill levels of prospective physics teachers on problem posing were determined and their views on problem posing were evaluated. To this end, prospective teachers were given…
Cancer risk assessment of polycyclic aromatic hydrocarbon contaminated soils determined using bioassay-derived levels of benzo[a]pyrene equivalents.

PubMed

Lemieux, Christine L; Long, Alexandra S; Lambert, Iain B; Lundstedt, Staffan; Tysklind, Mats; White, Paul A

2015-02-03

Here we evaluate the excess lifetime cancer risk (ELCR) posed by 10 PAH-contaminated soils using (i) the currently advocated, targeted chemical-specific approach that assumes dose additivity for carcinogenic PAHs and (ii) a bioassay-based approach that employs the in vitro mutagenic activity of the soil fractions to determine levels of benzo[a]pyrene equivalents and, by extension, ELCR. Mutagenic activity results are presented in our companion paper.1 The results show that ELCR values for the PAH-containing fractions, determined using the chemical-specific approach, are generally (i.e., 8 out of 10) greater than those calculated using the bioassay-based approach; most are less than 5-fold greater. Only two chemical-specific ELCR estimates are less than their corresponding bioassay-derived values; differences are less than 10%. The bioassay-based approach, which permits estimation of ELCR without a priori knowledge of mixture composition, proved to be a useful tool to evaluate the chemical-specific approach. The results suggest that ELCR estimates for complex PAH mixtures determined using a targeted, chemical-specific approach are reasonable, albeit conservative. Calculated risk estimates still depend on contentious PEFs and cancer slope factors. Follow-up in vivo mutagenicity assessments will be required to validate the results and their relevance for human health risk assessment of PAH-contaminated soils.
Impacts of discarded coffee waste on human and environmental health.

PubMed

Fernandes, A S; Mello, F V C; Thode Filho, S; Carpes, R M; Honório, J G; Marques, M R C; Felzenszwalb, I; Ferraz, E R A

2017-07-01

Coffee is one of the most widely consumed beverages throughout the world. So far, many studies have shown the properties of coffee beverages, but little is known about its impacts on human and environmental health from its discard in the environment. So, the present work aims to investigate the mutagenic, genotoxic, cytotoxic and ecotoxic effects of leached (LE) and solubilized (SE) extracts from coffee waste, simulating the disposal of this residue in landfills and via sewage systems, respectively. Chemical analyses were also carried out. LE and SE induced mutagenicity in the TA98 Salmonella strain with and without exogenous metabolization (S9). In the TA100 only SE induced mutagenicity, what was observed without S9. An increase in the frequency of micronuclei was observed in HepG2 cell line after 3 and 24h of exposure to both extracts. No cytotoxic effects were observed in HepG2 cells by WST-1 assay. The EC50 values for the LE and SE were 1.5% and 11.26% for Daphnia similis, 0.12% and 1.39% for Ceriodaphnia dubia and 6.0% and 5.5% for Vibrio fischeri, respectively. Caffeine and several transition metals were found in both extracts. Coffee waste discarded in the environment may pose a risk to human and environmental health, since this compound can cause DNA damage and present toxicity to aquatic organisms. Copyright © 2017 Elsevier Inc. All rights reserved.
Determining the Performances of Pre-Service Primary School Teachers in Problem Posing Situations

ERIC Educational Resources Information Center

Kilic, Cigdem

2013-01-01

This study examined the problem posing strategies of pre-service primary school teachers in different problem posing situations (PPSs) and analysed the issues they encounter while posing problems. A problem posing task consisting of six PPSs (two free, two structured, and two semi-structured situations) was delivered to 40 participants.…
Embedding Game-Based Problem-Solving Phase into Problem-Posing System for Mathematics Learning

ERIC Educational Resources Information Center

Chang, Kuo-En; Wu, Lin-Jung; Weng, Sheng-En; Sung, Yao-Ting

2012-01-01

A problem-posing system is developed with four phases including posing problem, planning, solving problem, and looking back, in which the "solving problem" phase is implemented by game-scenarios. The system supports elementary students in the process of problem-posing, allowing them to fully engage in mathematical activities. In total, 92 fifth…
Characteristics of Problem Posing of Grade 9 Students on Geometric Tasks

ERIC Educational Resources Information Center

Chua, Puay Huat; Wong, Khoon Yoong

2012-01-01

This is an exploratory study into the individual problem-posing characteristics of 480 Grade 9 Singapore students who were novice problem posers working on two geometric tasks. The students were asked to pose a problem for their friends to solve. Analyses of solvable posed problems were based on the problem type, problem information, solution type…
Problem Posing with the Multiplication Table

ERIC Educational Resources Information Center

Dickman, Benjamin

2014-01-01

Mathematical problem posing is an important skill for teachers of mathematics, and relates readily to mathematical creativity. This article gives a bit of background information on mathematical problem posing, lists further references to connect problem posing and creativity, and then provides 20 problems based on the multiplication table to be…
Investigation of Problem-Solving and Problem-Posing Abilities of Seventh-Grade Students

ERIC Educational Resources Information Center

Arikan, Elif Esra; Ünal, Hasan

2015-01-01

This study aims to examine the effect of multiple problem-solving skills on the problem-posing abilities of gifted and non-gifted students and to assess whether the possession of such skills can predict giftedness or affect problem-posing abilities. Participants' metaphorical images of problem posing were also explored. Participants were 20 gifted…
Cytotoxic, phytotoxic, and mutagenic appraisal to ascertain toxicological potential of particulate matter emitted from automobiles.

PubMed

Anwar, Khaleeq; Ejaz, Sohail; Ashraf, Muhammad; Altaf, Imran; Anjum, Aftab Ahmad

2013-07-01

Vehicular air pollution is a mounting health issue of the modern age, particularly in urban populations of the developing nations. Auto-rickshaws are not considered eco-friendly as to their inefficient engines producing large amount of particulate matter (PM), thus posing significant environmental threat. The present study was conducted to ascertain the cytotoxic, phytotoxic, and mutagenic potential of PM from gasoline-powered two-stroke auto-rickshaws (TSA) and compressed natural gas-powered four-stroke auto-rickshaws (FSA). Based on the increased amount of aluminum quantified during proton-induced X-ray emission analysis of PM from TSA and FSA, different concentrations of aluminum sulfate were also tested to determine its eco-toxicological potential. The MTT assay demonstrated significant (p < 0.001) dose-dependent cytotoxic effects of different concentrations of TSA, FSA, and aluminum sulfate on BHK-21 cell line. LC50 of TSA, FSA, and aluminum sulfate was quantified at 16, 11, and 23.8 μg/ml, respectively, establishing PM from FSA, a highly cytotoxic material. In case of phytotoxicity screening using Zea mays, the results demonstrated that all three tested materials were equally phytotoxic at higher concentrations producing significant reduction (p < 0.001) in seed germination. Aluminum sulfate proved to be a highly phytotoxic agent even at its lowest concentration. Mutagenicity was assessed by fluctuation Salmonella reverse mutation assay adopting TA100 and TA98 mutant strains with (+S9) and without (-S9) metabolic activation. Despite the fact that different concentrations of PM from both sources, i.e., TSA and FSA were highly mutagenic (p < 0.001) even at lower concentrations, the mutagenic index was higher in TSA. Data advocate that all tested materials are equally ecotoxic, and if the existing trend of atmospheric pollution by auto-rickshaws is continued, airborne heavy metals will seriously affect the normal growth of local inhabitants and increased contamination of agricultural products, which will amplify the dietary intake of the toxic elements and could result in genetic mutation or long-term health implications.
Some Reflections on Problem Posing: A Conversation with Marion Walter

ERIC Educational Resources Information Center

Baxter, Juliet A.

2005-01-01

Marion Walter, an internationally acclaimed mathematics educator discusses about problem posing, focusing on both the merits of problem posing and techniques to encourage problem posing. She believes that playful attitude toward problem variables is an essential part of an inquiring mind and the more opportunities that learners have, to change a…
Investigation of learning environment for arithmetic word problems by problem posing as sentence integration in Indonesian language

NASA Astrophysics Data System (ADS)

Hasanah, N.; Hayashi, Y.; Hirashima, T.

2017-02-01

Arithmetic word problems remain one of the most difficult area of teaching mathematics. Learning by problem posing has been suggested as an effective way to improve students’ understanding. However, the practice in usual classroom is difficult due to extra time needed for assessment and giving feedback to students’ posed problems. To address this issue, we have developed a tablet PC software named Monsakun for learning by posing arithmetic word problems based on Triplet Structure Model. It uses the mechanism of sentence-integration, an efficient implementation of problem-posing that enables agent-assessment of posed problems. The learning environment has been used in actual Japanese elementary school classrooms and the effectiveness has been confirmed in previous researches. In this study, ten Indonesian elementary school students living in Japan participated in a learning session of problem posing using Monsakun in Indonesian language. We analyzed their learning activities and show that students were able to interact with the structure of simple word problem using this learning environment. The results of data analysis and questionnaire suggested that the use of Monsakun provides a way of creating an interactive and fun environment for learning by problem posing for Indonesian elementary school students.
Applicability domains for classification problems: benchmarking of distance to models for AMES mutagenicity set

EPA Science Inventory

For QSAR and QSPR modeling of biological and physicochemical properties, estimating the accuracy of predictions is a critical problem. The “distance to model” (DM) can be defined as a metric that defines the similarity between the training set molecules and the test set compound ...
Analyses of the genotoxic and mutagenic potential of the products formed after the biotransformation of the azo dye Disperse Red 1.

PubMed

Chequer, Farah Maria Drumond; Lizier, Thiago Mescoloto; de Felício, Rafael; Zanoni, Maria Valnice Boldrin; Debonsi, Hosana Maria; Lopes, Norberto Peporine; Marcos, Ricard; de Oliveira, Danielle Palma

2011-12-01

Azo dyes constitute the largest class of synthetic dyes. Following oral exposure, these dyes can be reduced to aromatic amines by the intestinal microflora or liver enzymes. This work identified the products formed after oxidation and reduction of the dye Disperse Red 1, simulating hepatic biotransformation and evaluated the mutagenic potential of the resultant solution. Controlled potential electrolysis was carried out on dye solution using a Potentiostat/Galvanostat. HPLC-DAD and GC/MS were used to determine the products generated after the oxidation/reduction process. The Salmonella/microsome assay with the strains TA98 and YG1041 without S9, and the mouse lymphoma assay (MLA) using the thymidine kinase (Tk) gene, were used to evaluate the mutagenicity of the products formed. Sulfate 2-[(4-aminophenyl)ethylamino]-ethanol monohydrate, nitrobenzene, 4-nitro-benzamine and 2-(ethylphenylamino)-ethanol were detected. This dye has already being assigned as mutagenic in different cell system. In addition, after the oxidation/reduction process the dye still had mutagenic activity for the Salmonella/microsome assay. Nevertheless, both the original dye Disperse Red 1 and its treated solutions showed negative results in the MLA. The present results suggest that the ingestion of water and food contaminated with this dye may represent human and environmental health problem, due to the generation of harmful compounds after biotransformation. Copyright © 2011 Elsevier Ltd. All rights reserved.
Problem Posing as a Pedagogical Strategy: A Teacher's Perspective

ERIC Educational Resources Information Center

Staebler-Wiseman, Heidi A.

2011-01-01

Student problem posing has been advocated for mathematics instruction, and it has been suggested that problem posing can be used to develop students' mathematical content knowledge. But, problem posing has rarely been utilized in university-level mathematics courses. The goal of this teacher-as-researcher study was to develop and investigate…
Students’ Creativity: Problem Posing in Structured Situation

NASA Astrophysics Data System (ADS)

Amalina, I. K.; Amirudin, M.; Budiarto, M. T.

2018-01-01

This is a qualitative research concerning on students’ creativity on problem posing task. The study aimed at describing the students’ creative thinking ability to pose the mathematics problem in structured situations with varied condition of given problems. In order to find out the students’ creative thinking ability, an analysis of mathematics problem posing test based on fluency, novelty, and flexibility and interview was applied for categorizing students’ responses on that task. The data analysis used the quality of problem posing and categorized in 4 level of creativity. The results revealed from 29 secondary students grade 8, a student in CTL (Creative Thinking Level) 1 met the fluency. A student in CTL 2 met the novelty, while a student in CTL 3 met both fluency and novelty and no one in CTL 4. These results are affected by students’ mathematical experience. The findings of this study highlight that student’s problem posing creativity are dependent on their experience in mathematics learning and from the point of view of which students start to pose problem.
[Principles of establishing occupational exposure limits for carcinogens in Poland and in other EU countries].

PubMed

Skowroń, Jolanta; Czerczak, Slawomir

2013-01-01

The principles of determining exposure limits for carcinogens adopted in Poland, the European Union and in other selected countries of the EC are discussed in this article. Carcinogens and/or mutagens pose a direct health risk to people exposed to them. If carcinogens cannot be eliminated from the work and living environments, their exposure should be kept at the lowest possible level. To assess health risk for carcinogens it is necessary to determine the probability of developing a disease or of death from cancer as a result of occupational exposure to carcinogenic substances.

Results of a round-robin exercise on read-across.

PubMed

Benfenati, E; Belli, M; Borges, T; Casimiro, E; Cester, J; Fernandez, A; Gini, G; Honma, M; Kinzl, M; Knauf, R; Manganaro, A; Mombelli, E; Petoumenou, M I; Paparella, M; Paris, P; Raitano, G

2016-05-01

A round-robin exercise was conducted within the CALEIDOS LIFE project. The participants were invited to assess the hazard posed by a substance, applying in silico methods and read-across approaches. The exercise was based on three endpoints: mutagenicity, bioconcentration factor and fish acute toxicity. Nine chemicals were assigned for each endpoint and the participants were invited to complete a specific questionnaire communicating their conclusions. The interesting aspect of this exercise is the justification behind the answers more than the final prediction in itself. Which tools were used? How did the approach selected affect the final answer?
Assessing Students' Mathematical Problem Posing

ERIC Educational Resources Information Center

Silver, Edward A.; Cai, Jinfa

2005-01-01

Specific examples are used to discuss assessment, an integral part of mathematics instruction, with problem posing and assessment of problem posing. General assessment criteria are suggested to evaluate student-generated problems in terms of their quantity, originality, and complexity.
Engaging Pre-Service Middle-School Teacher-Education Students in Mathematical Problem Posing: Development of an Active Learning Framework

ERIC Educational Resources Information Center

Ellerton, Nerida F.

2013-01-01

Although official curriculum documents make cursory mention of the need for problem posing in school mathematics, problem posing rarely becomes part of the implemented or assessed curriculum. This paper provides examples of how problem posing can be made an integral part of mathematics teacher education programs. It is argued that such programs…
Creativity and Mathematical Problem Posing: An Analysis of High School Students' Mathematical Problem Posing in China and the USA

ERIC Educational Resources Information Center

Van Harpen, Xianwei Y.; Sriraman, Bharath

2013-01-01

In the literature, problem-posing abilities are reported to be an important aspect/indicator of creativity in mathematics. The importance of problem-posing activities in mathematics is emphasized in educational documents in many countries, including the USA and China. This study was aimed at exploring high school students' creativity in…
Interlocked Problem Posing and Children's Problem Posing Performance in Free Structured Situations

ERIC Educational Resources Information Center

Cankoy, Osman

2014-01-01

The aim of this study is to explore the mathematical problem posing performance of students in free structured situations. Two classes of fifth grade students (N = 30) were randomly assigned to experimental and control groups. The categories of the problems posed in free structured situations by the 2 groups of students were studied through…
Problem-Posing Strategies Used by Years 8 and 9 Students

ERIC Educational Resources Information Center

Stoyanova, Elena

2005-01-01

According to Kilpatrick (1987), in the mathematics classrooms problem posing can be applied as a "goal" or as a means of instruction. Using problem posing as a goal of instruction involves asking students to respond to a range of problem-posing prompts. The main goal of this article is a classification of mathematics questions created by Years 8…
When a Problem Is More than a Teacher's Question

ERIC Educational Resources Information Center

Olson, Jo Clay; Knott, Libby

2013-01-01

Not only are the problems teachers pose throughout their teaching of great importance but also the ways in which they use those problems make this a critical component of teaching. A problem-posing episode includes the problem setup, the statement of the problem, and the follow-up questions. Analysis of problem-posing episodes of precalculus…
An Analysis of Secondary and Middle School Teachers' Mathematical Problem Posing

ERIC Educational Resources Information Center

Stickles, Paula R.

2011-01-01

This study identifies the kinds of problems teachers pose when they are asked to (a) generate problems from given information and (b) create new problems from ones given to them. To investigate teachers' problem posting, preservice and inservice teachers completed background questionnaires and four problem-posing instruments. Based on previous…
Analysis of Problems Posed by Sixth-Grade Middle School Students for the Addition of Fractions in Terms of Semantic Structures

ERIC Educational Resources Information Center

Kar, Tugrul

2015-01-01

This study aimed to investigate how the semantic structures of problems posed by sixth-grade middle school students for the addition of fractions affect their problem-posing performance. The students were presented with symbolic operations involving the addition of fractions and asked to pose two different problems related to daily-life situations…
Unraveling the Mystery of the Origin of Mathematical Problems: Using a Problem-Posing Framework with Prospective Mathematics Teachers

ERIC Educational Resources Information Center

Contreras, Jose

2007-01-01

In this article, I model how a problem-posing framework can be used to enhance our abilities to systematically generate mathematical problems by modifying the attributes of a given problem. The problem-posing model calls for the application of the following fundamental mathematical processes: proving, reversing, specializing, generalizing, and…
Cytotoxicity and genotoxicity properties of particulate matter fraction 2.5 μm

NASA Astrophysics Data System (ADS)

Bełcik, Maciej K.; Trusz-Zdybek, Agnieszka; Zaczyńska, Ewa; Czarny, Anna; Piekarska, Katarzyna

2017-11-01

In the ambient is more than 2,000 chemical substances, some of them are absorbed on the surface of the particulate matter and may causes many health problems. Air pollution is responsible for more than 3.2 million premature deaths which classifies it as a second place environmental risk factor. Especially dangerous for health are polycyclic aromatic hydrocarbons and their nitro- and amino derivatives which shows mutagenic and carcinogenic properties. Air pollutions were also classified by International Agency for Research on Cancer to group which carcinogenic properties on human were proved by available knowledge. Air pollutions, including particulate matter are one of the biggest problem in Polish cities. World Health Organization in report published in May 2016 set many of Polish cities on the top of the list most polluted in European Union. The article presents results of mutagenicity, genotoxicity and cytotoxicity researches conducted on a particulate matter fraction 2.5 μm collected during all year long in Wroclaw agglomeration. The material were collected on filters using high-flow air aspirator and extracted using dichloromethane. Additionally it was fractionated into 2 parts containing: all pollutants and only polycyclic aromatic hydrocarbons. Dry residue of this fractions were dissolving in DMSO and tested using biological methods. Biological methods include mutagenicity properties which are investigated by Salmonella assay (Ames assay). Other biological method was comet assay and 4 parameter cytotoxicity test PAN-I assay. Results of the conducted experiments shows differences in mutagenic, genotoxic and cytotoxic properties between seasons of collection and between volume of dust pollutions fractions. The worst properties shows particles collected in autumn and winter season and this containing only polycyclic aromatics hydrocarbons. Results showed also some correlations in results obtained during different methods and properties.
UV light-induced survival response in a highly radiation-resistant isolate of the Moraxella-acinetobacter group

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, L.C.; Thompson, T.L.; Maxcy, R.B.

1982-02-01

A highly radiation-resistant member of the Moraxella-Acinetobacter group, isolate 4, obtained from meat, was studied to determine the effect of preexposure to UV radiation on subsequent UV light resistance. Cultures that were preexposed to UV light and incubated for a short time in plate count broth exhibited increased survival of a UV light challenge dose. This response was inhibited in the presence of chloramphenicol. Frequencies of mutation to streptomycin, trimethoprim, and sulfanilamide resistance remained the same after the induction of this survival response and were not altered by treatment with mutagens, with the exception of mutation to streptomycin resistance aftermore » ..gamma..-irradiation or nitrosoguanidine or methyl methane sulfonate treatment. The results indicated that isolate 4 has a UV light-inducible UV light resistance mechanism which is not associated with increased mutagenesis. The characteristics of the radiation resistance response in this organism are similar to those of certain other common food contaminants. Therefore, considered as part of the total microflora of meat, isolate 4 and the other radiation-resistant Moraxella-Acinetobacter isolates should not pose unique problems in a proposed radappertizaton process.« less
A New Problem-Posing Approach Based on Problem-Solving Strategy: Analyzing Pre-Service Primary School Teachers' Performance

ERIC Educational Resources Information Center

Kiliç, Çigdem

2017-01-01

This study examined pre-service primary school teachers' performance in posing problems that require knowledge of problem-solving strategies. Quantitative and qualitative methods were combined. The 120 participants were asked to pose a problem that could be solved by using the find-a-pattern a particular problem-solving strategy. After that,…
Artifacts as Sources for Problem-Posing Activities

ERIC Educational Resources Information Center

Bonotto, Cinzia

2013-01-01

The problem-posing process represents one of the forms of authentic mathematical inquiry which, if suitably implemented in classroom activities, could move well beyond the limitations of word problems, at least as they are typically utilized. The two exploratory studies presented sought to investigate the impact of "problem-posing" activities when…
The Art of Problem Posing. 3rd Edition

ERIC Educational Resources Information Center

Brown, Stephen I.; Walter, Marion I.

2005-01-01

The new edition of this classic book describes and provides a myriad of examples of the relationships between problem posing and problem solving, and explores the educational potential of integrating these two activities in classrooms at all levels. "The Art of Problem Posing, Third Edition" encourages readers to shift their thinking…
An Investigation on Chinese Teachers' Realistic Problem Posing and Problem Solving Ability and Beliefs

ERIC Educational Resources Information Center

Chen, Limin; Van Dooren, Wim; Chen, Qi; Verschaffel, Lieven

2011-01-01

In the present study, which is a part of a research project about realistic word problem solving and problem posing in Chinese elementary schools, a problem solving and a problem posing test were administered to 128 pre-service and in-service elementary school teachers from Tianjin City in China, wherein the teachers were asked to solve 3…
Enhancing students’ mathematical problem posing skill through writing in performance tasks strategy

NASA Astrophysics Data System (ADS)

Kadir; Adelina, R.; Fatma, M.

2018-01-01

Many researchers have studied the Writing in Performance Task (WiPT) strategy in learning, but only a few paid attention on its relation to the problem-posing skill in mathematics. The problem-posing skill in mathematics covers problem reformulation, reconstruction, and imitation. The purpose of the present study was to examine the effect of WiPT strategy on students’ mathematical problem-posing skill. The research was conducted at a Public Junior Secondary School in Tangerang Selatan. It used a quasi-experimental method with randomized control group post-test. The samples were 64 students consists of 32 students of the experiment group and 32 students of the control. A cluster random sampling technique was used for sampling. The research data were obtained by testing. The research shows that the problem-posing skill of students taught by WiPT strategy is higher than students taught by a conventional strategy. The research concludes that the WiPT strategy is more effective in enhancing the students’ mathematical problem-posing skill compared to the conventional strategy.
Dissecting Success Stories on Mathematical Problem Posing: A Case of the Billiard Task

ERIC Educational Resources Information Center

Koichu, Boris; Kontorovich, Igor

2013-01-01

"Success stories," i.e., cases in which mathematical problems posed in a controlled setting are perceived by the problem posers or other individuals as interesting, cognitively demanding, or surprising, are essential for understanding the nature of problem posing. This paper analyzes two success stories that occurred with individuals of different…
What Makes a Problem Mathematically Interesting? Inviting Prospective Teachers to Pose Better Problems

ERIC Educational Resources Information Center

Crespo, Sandra; Sinclair, Nathalie

2008-01-01

School students of all ages, including those who subsequently become teachers, have limited experience posing their own mathematical problems. Yet problem posing, both as an act of mathematical inquiry and of mathematics teaching, is part of the mathematics education reform vision that seeks to promote mathematics as an worthy intellectual…
Helping Young Students to Better Pose an Environmental Problem

ERIC Educational Resources Information Center

Pruneau, Diane; Freiman, Viktor; Barbier, Pierre-Yves; Langis, Joanne

2009-01-01

Grade 3 students were asked to solve a sedimentation problem in a local river. With scientists, students explored many aspects of the problem and proposed solutions. Graphic representation tools were used to help students to better pose the problem. Using questionnaires and interviews, researchers observed students' capacity to pose the problem…

University Students' Problem Posing Abilities and Attitudes towards Mathematics.

ERIC Educational Resources Information Center

Grundmeier, Todd A.

2002-01-01

Explores the problem posing abilities and attitudes towards mathematics of students in a university pre-calculus class and a university mathematical proof class. Reports a significant difference in numeric posing versus non-numeric posing ability in both classes. (Author/MM)
Effects of the Problem-Posing Approach on Students' Problem Solving Skills and Metacognitive Awareness in Science Education

NASA Astrophysics Data System (ADS)

Akben, Nimet

2018-05-01

The interrelationship between mathematics and science education has frequently been emphasized, and common goals and approaches have often been adopted between disciplines. Improving students' problem-solving skills in mathematics and science education has always been given special attention; however, the problem-posing approach which plays a key role in mathematics education has not been commonly utilized in science education. As a result, the purpose of this study was to better determine the effects of the problem-posing approach on students' problem-solving skills and metacognitive awareness in science education. This was a quasi-experimental based study conducted with 61 chemistry and 40 physics students; a problem-solving inventory and a metacognitive awareness inventory were administered to participants both as a pre-test and a post-test. During the 2017-2018 academic year, problem-solving activities based on the problem-posing approach were performed with the participating students during their senior year in various university chemistry and physics departments throughout the Republic of Turkey. The study results suggested that structured, semi-structured, and free problem-posing activities improve students' problem-solving skills and metacognitive awareness. These findings indicated not only the usefulness of integrating problem-posing activities into science education programs but also the need for further research into this question.
Analyzing Pre-Service Primary Teachers' Fraction Knowledge Structures through Problem Posing

ERIC Educational Resources Information Center

Kilic, Cigdem

2015-01-01

In this study it was aimed to determine pre-service primary teachers' knowledge structures of fraction through problem posing activities. A total of 90 pre-service primary teachers participated in this study. A problem posing test consisting of two questions was used and the participants were asked to generate as many as problems based on the…
Students’ Mathematical Creative Thinking through Problem Posing Learning

NASA Astrophysics Data System (ADS)

Ulfah, U.; Prabawanto, S.; Jupri, A.

2017-09-01

The research aims to investigate the differences in enhancement of students’ mathematical creative thinking ability of those who received problem posing approach assisted by manipulative media and students who received problem posing approach without manipulative media. This study was a quasi experimental research with non-equivalent control group design. Population of this research was third-grade students of a primary school in Bandung city in 2016/2017 academic year. Sample of this research was two classes as experiment class and control class. The instrument used is a test of mathematical creative thinking ability. Based on the results of the research, it is known that the enhancement of the students’ mathematical creative thinking ability of those who received problem posing approach with manipulative media aid is higher than the ability of those who received problem posing approach without manipulative media aid. Students who get learning problem posing learning accustomed in arranging mathematical sentence become matter of story so it can facilitate students to comprehend about story
Mutagenicity in a Molecule: Identification of Core Structural Features of Mutagenicity Using a Scaffold Analysis

PubMed Central

Hsu, Kuo-Hsiang; Su, Bo-Han; Tu, Yi-Shu; Lin, Olivia A.; Tseng, Yufeng J.

2016-01-01

With advances in the development and application of Ames mutagenicity in silico prediction tools, the International Conference on Harmonisation (ICH) has amended its M7 guideline to reflect the use of such prediction models for the detection of mutagenic activity in early drug safety evaluation processes. Since current Ames mutagenicity prediction tools only focus on functional group alerts or side chain modifications of an analog series, these tools are unable to identify mutagenicity derived from core structures or specific scaffolds of a compound. In this study, a large collection of 6512 compounds are used to perform scaffold tree analysis. By relating different scaffolds on constructed scaffold trees with Ames mutagenicity, four major and one minor novel mutagenic groups of scaffold are identified. The recognized mutagenic groups of scaffold can serve as a guide for medicinal chemists to prevent the development of potentially mutagenic therapeutic agents in early drug design or development phases, by modifying the core structures of mutagenic compounds to form non-mutagenic compounds. In addition, five series of substructures are provided as recommendations, for direct modification of potentially mutagenic scaffolds to decrease associated mutagenic activities. PMID:26863515
Process-based Assignment-Setting Change for Support of Overcoming Bottlenecks in Learning by Problem-Posing in Arithmetic Word Problems

NASA Astrophysics Data System (ADS)

Supianto, A. A.; Hayashi, Y.; Hirashima, T.

2017-02-01

Problem-posing is well known as an effective activity to learn problem-solving methods. Monsakun is an interactive problem-posing learning environment to facilitate arithmetic word problems learning for one operation of addition and subtraction. The characteristic of Monsakun is problem-posing as sentence-integration that lets learners make a problem of three sentences. Monsakun provides learners with five or six sentences including dummies, which are designed through careful considerations by an expert teacher as a meaningful distraction to the learners in order to learn the structure of arithmetic word problems. The results of the practical use of Monsakun in elementary schools show that many learners have difficulties in arranging the proper answer at the high level of assignments. The analysis of the problem-posing process of such learners found that their misconception of arithmetic word problems causes impasses in their thinking and mislead them to use dummies. This study proposes a method of changing assignments as a support for overcoming bottlenecks of thinking. In Monsakun, the bottlenecks are often detected as a frequently repeated use of a specific dummy. If such dummy can be detected, it is the key factor to support learners to overcome their difficulty. This paper discusses how to detect the bottlenecks and to realize such support in learning by problem-posing.
The Problems Posed and Models Employed by Primary School Teachers in Subtraction with Fractions

ERIC Educational Resources Information Center

Iskenderoglu, Tuba Aydogdu

2017-01-01

Students have difficulties in solving problems of fractions in almost all levels, and in problem posing. Problem posing skills influence the process of development of the behaviors observed at the level of comprehension. That is why it is very crucial for teachers to develop activities for student to have conceptual comprehension of fractions and…
Problem-Posing Research in Mathematics Education: Looking Back, Looking Around, and Looking Ahead

ERIC Educational Resources Information Center

Silver, Edward A.

2013-01-01

In this paper, I comment on the set of papers in this special issue on mathematical problem posing. I offer some observations about the papers in relation to several key issues, and I suggest some productive directions for continued research inquiry on mathematical problem posing.
URINARY MUTAGENICITY AS A BIOMARKER OF COOKED-MEAT-ASSOCIATED MUTAGENS AND RISK FOR COLORECTAL ADENOMA

EPA Science Inventory

Urinary Mutagenicity as a Biomarker of Cooked-Meat-Associated Mutagens and Risk for Colorectal Adenoma

In a controlled feeding study involving 60 subjects, we have investigated urinary mutagenicity as a biomarker of exposure to cooked-meat-associated mutagens. In a separa...
Mikrobielle Kurzzeitteste zur Bestimmung der mutagenen Potenz chemischer Substanzen

NASA Astrophysics Data System (ADS)

Gericke, Dietmar

1983-04-01

During the last 20 years it became much more interesting to test new chemicals as fast as possible for their carcinogenic potency. Therefore new test models were developed. Mutagenicity seems to be one sign for carcinogenicity. Therefore test systems using microorganisms were studied which are influenced by mutagenic substances. These systems are described, first of all the Ames-Test, using revertants of Salmonella typhimurium, secondly the Escherichia coli system deficient of DNA-polymerase A (DNA-Pol A-). The yeast Saccharomyces cerevisiae was introduced some years ago and finally the Neurospora crassa system serves as an additional test to define exactly the localisation of mutations. The tests and their problems are discussed.
Genotoxicity Evaluation of Irrigative Wastewater from Shijiazhuang City in China

PubMed Central

Yang, Lixue; Zhang, Xiaolin; Wang, Liqin; Yu, Fengxue; Liu, Yi; Chen, Qing; Liu, Dianwu

2015-01-01

In the present study, the wastewater sample collected from the Dongming discharging river in Shijiazhuang city was analysed using both chemical analysis and biological assays including the Salmonella mutagenicity test, micronucleus test and single-cell gel electrophoresis. Chemical analysis of the sample was performed using gas chromatography mass spectrometry and inductively coupled plasma mass spectrometry. The Salmonella mutagenicity test was performed on Salmonella typhimurium TA97, TA98, TA100 and TA102 strains with and without S9 mixture. The mice received the wastewater in natura through drinking water at concentrations of 25%, 50%, and 100%. One group of mice was exposed for 2 consecutive days, and the other group of mice was exposed for 15 consecutive days. To establish the levels of primary DNA damage, single-cell gel electrophoresis was performed on treated mouse liver cell. The concentrations of chromium and lead in the sample exceeded the national standard (GB20922-2007) by 0.78 and 0.43-fold, respectively. More than 30 organic compounds were detected, and some of the detected compounds were mutagens, carcinogens and environmental endocrine disrupters. A positive response for Salmonella typhimurium TA98 strain was observed. Mouse exposure via drinking water containing 50% and 100% of wastewater for 15 consecutive days caused a significant increase of MN frequencies in a dose-response manner. Mouse exposure via drinking water containing 50% and 100% of wastewater for 15 consecutive days caused a significant increase of the Olive tail moments in a dose-response manner. All the results indicated that the sample from the Dongming discharging river in Shijiazhuang city exhibited genotoxicity and might pose harmful effects on the local residents. PMID:26658348
An Exploratory Framework for Handling the Complexity of Mathematical Problem Posing in Small Groups

ERIC Educational Resources Information Center

Kontorovich, Igor; Koichu, Boris; Leikin, Roza; Berman, Avi

2012-01-01

The paper introduces an exploratory framework for handling the complexity of students' mathematical problem posing in small groups. The framework integrates four facets known from past research: task organization, students' knowledge base, problem-posing heuristics and schemes, and group dynamics and interactions. In addition, it contains a new…
Problem Posing at All Levels in the Calculus Classroom

ERIC Educational Resources Information Center

Perrin, John Robert

2007-01-01

This article explores the use of problem posing in the calculus classroom using investigative projects. Specially, four examples of student work are examined, each one differing in originality of problem posed. By allowing students to explore actual questions that they have about calculus, coming from their own work or class discussion, or…
Critical Inquiry across the Disciplines: Strategies for Student-Generated Problem Posing

ERIC Educational Resources Information Center

Nardone, Carroll Ferguson; Lee, Renee Gravois

2011-01-01

Problem posing is a higher-order, active-learning task that is important for students to develop. This article describes a series of interdisciplinary learning activities designed to help students strengthen their problem-posing skills, which requires that students become more responsible for their learning and that faculty move to a facilitator…
Developing Teachers' Subject Didactic Competence through Problem Posing

ERIC Educational Resources Information Center

Ticha, Marie; Hospesova, Alena

2013-01-01

Problem posing (not only in lesson planning but also directly in teaching whenever needed) is one of the attributes of a teacher's subject didactic competence. In this paper, problem posing in teacher education is understood as an educational and a diagnostic tool. The results of the study were gained in pre-service primary school teacher…
The Impact of Problem Posing on Elementary Teachers' Beliefs about Mathematics and Mathematics Teaching

ERIC Educational Resources Information Center

Barlow, Angela T.; Cates, Janie M.

2006-01-01

This study investigated the impact of incorporating problem posing in elementary classrooms on the beliefs held by elementary teachers about mathematics and mathematics teaching. Teachers participated in a year-long staff development project aimed at facilitating the incorporation of problem posing into their classrooms. Beliefs were examined via…
The Posing of Arithmetic Problems by Mathematically Talented Students

ERIC Educational Resources Information Center

Espinoza González, Johan; Lupiáñez Gómez, José Luis; Segovia Alex, Isidoro

2016-01-01

Introduction: This paper analyzes the arithmetic problems posed by a group of mathematically talented students when given two problem-posing tasks, and compares these students' responses to those given by a standard group of public school students to the same tasks. Our analysis focuses on characterizing and identifying the differences between the…
Posing Problems to Understand Children's Learning of Fractions

ERIC Educational Resources Information Center

Cheng, Lu Pien

2013-01-01

In this study, ways in which problem posing activities aid our understanding of children's learning of addition of unlike fractions and product of proper fractions was examined. In particular, how a simple problem posing activity helps teachers take a second, deeper look at children's understanding of fraction concepts will be discussed. The…
Development of the Structured Problem Posing Skills and Using Metaphoric Perceptions

ERIC Educational Resources Information Center

Arikan, Elif Esra; Unal, Hasan

2014-01-01

The purpose of this study was to introduce problem posing activity to third grade students who have never met before. This study was also explored students' metaphorical images on problem posing process. Participants were from Public school in Marmara Region in Turkey. Data was analyzed both qualitatively (content analysis for difficulty and…
Integrating Worked Examples into Problem Posing in a Web-Based Learning Environment

ERIC Educational Resources Information Center

Hsiao, Ju-Yuan; Hung, Chun-Ling; Lan, Yu-Feng; Jeng, Yoau-Chau

2013-01-01

Most students always lack of experience and perceive difficult regarding problem posing. The study hypothesized that worked examples may have benefits for supporting students' problem posing activities. A quasi-experiment was conducted in the context of a business mathematics course for examining the effects of integrating worked examples into…

Mutagenicity of automobile workshop soil leachate and tobacco industry wastewater using the Ames Salmonella fluctuation and the SOS chromotests.

PubMed

Okunola, Alabi A; Babatunde, Esan E; Chinwe, Duru; Pelumi, Oyedele; Ramatu, Salihu G

2016-06-01

Environmental management of industrial solid wastes and wastewater is an important economic and environmental health problem globally. This study evaluated the mutagenic potential of automobile workshop soil-simulated leachate and tobacco wastewater using the SOS chromotest on Escherichia coli PQ37 and the Ames Salmonella fluctuation test on Salmonella typhimurium strains TA98 and TA100 without metabolic activation. Physicochemical parameters of the samples were also analyzed. The result of the Ames test showed mutagenicity of the test samples. However, the TA100 was the more responsive strain for both the simulated leachate and tobacco wastewater in terms of mutagenic index in the absence of metabolic activation. The SOS chromotest results were in agreement with those of the Ames Salmonella fluctuation test. Nevertheless, the E. coli PQ37 system was slightly more sensitive than the Salmonella assay for detecting genotoxins in the tested samples. Iron, cadmium, manganese, copper, nickel, chromium, arsenic, zinc, and lead contents analyzed in the samples were believed to play significant role in the observed mutagenicity in the microbial assays. The results of this study showed that the simulated leachate and tobacco wastewater showed strong indication of a genotoxic risk. Further studies would be required in the analytical field in order to identify and quantify other compounds not analyzed for in this study, some of which could be responsible for the observed genotoxicity. This will be necessary in order to identify the sources of toxicants and thus to take preventive and/or curative measures to limit the toxicity of these types of wastes. © The Author(s) 2014.
Toxicity, uptake, and mutagenicity of particulate and soluble nickel compounds.

PubMed Central

Fletcher, G G; Rossetto, F E; Turnbull, J D; Nieboer, E

1994-01-01

Toxicity testing in AS52 cells (24-hr exposures) gave LC50 values of 2 to 130 micrograms Ni/ml for particulate nickel compounds and 45 to 60 micrograms Ni/ml for water-soluble salts (NiCl2, NiSO4, Ni(CH3COO)2). The Ni(OH)2, NiCO3, and sulfides (Ni3S2, Ni7S6, "amorphous NiS") exhibited similar toxicities (LC50's of 2 to 8 micrograms Ni/ml), while three nickel oxides were more variable and less toxic (LC50's of 18 to 130 micrograms Ni/ml). Most compounds displayed nuclear to cytoplasmic nickel ratios of approximately 1:1.5 to 1:5 (except approximately 1:20 for nickel salts). At the LC50's, a 75-fold range in exposure levels occurred compared to a 10-fold range in cytoplasmic and nuclear nickel concentrations, [Ni]. Cellular nickel distribution indicated three groupings: inert compounds (green NiO, lithium nickel oxide, relatively low nuclear and cytosolic [Ni]); water-soluble salts (very low nuclear [Ni]; high cytosolic [Ni]), and slightly soluble compounds (relatively high cytosolic and nuclear [Ni]). Nickel compounds are considered to be only weak or equivocal mutagens. In this study, a low but significant increase in mutation rate at the gpt locus was shown. Although the results would not be sufficient to deem nickel compounds mutagenic by traditional criteria, characterization by PCR analysis indicated that the spontaneous and nickel-induced mutants exhibited different and compound-specific mutational spectra (thus confirming nickel compound involvement). The results reported illustrate some of the methodologic problems involved in testing "weak" mutagens and indicate that alternative approaches may be necessary in classifying the mutagenicity of nickel and other compounds. PMID:7843140
COMPARATIVE POTENCY OF COMPLEX MIXTURES: USE OF SHORT-TERM GENETIC BIOASSAYS IN CANCER RISK ASSESSMENT

EPA Science Inventory

The primary problem regarding the introduction of new energy sources is whether they will alter the mutagenicity, carcinogenicity and potential human cancer risk from combustion emissions. New risk assessment methodologies utilizing data from short-term bioassays, therefore, are ...
Developing Pre-Service Teachers Understanding of Fractions through Problem Posing

ERIC Educational Resources Information Center

Toluk-Ucar, Zulbiye

2009-01-01

This study investigated the effect of problem posing on the pre-service primary teachers' understanding of fraction concepts enrolled in two different versions of a methods course at a university in Turkey. In the experimental version, problem posing was used as a teaching strategy. At the beginning of the study, the pre-service teachers'…
The Effects of Problem Posing on Student Mathematical Learning: A Meta-Analysis

ERIC Educational Resources Information Center

Rosli, Roslinda; Capraro, Mary Margaret; Capraro, Robert M.

2014-01-01

The purpose of the study was to meta-synthesize research findings on the effectiveness of problem posing and to investigate the factors that might affect the incorporation of problem posing in the teaching and learning of mathematics. The eligibility criteria for inclusion of literature in the meta-analysis was: published between 1989 and 2011,…
Teachers Implementing Mathematical Problem Posing in the Classroom: Challenges and Strategies

ERIC Educational Resources Information Center

Leung, Shuk-kwan S.

2013-01-01

This paper reports a study about how a teacher educator shared knowledge with teachers when they worked together to implement mathematical problem posing (MPP) in the classroom. It includes feasible methods for getting practitioners to use research-based tasks aligned to the curriculum in order to encourage children to pose mathematical problems.…
Problem-Posing in Education: Transformation of the Practice of the Health Professional.

ERIC Educational Resources Information Center

Casagrande, L. D. R.; Caron-Ruffino, M.; Rodrigues, R. A. P.; Vendrusculo, D. M. S.; Takayanagui, A. M. M.; Zago, M. M. F.; Mendes, M. D.

1998-01-01

Studied the use of a problem-posing model in health education. The model based on the ideas of Paulo Freire is presented. Four innovative experiences of teaching-learning in environmental and occupational health and patient education are reported. Notes that the problem-posing model has the capability to transform health-education practice.…
Prospective Middle School Mathematics Teachers' Knowledge of Linear Graphs in Context of Problem-Posing

ERIC Educational Resources Information Center

Kar, Tugrul

2016-01-01

This study examined prospective middle school mathematics teachers' problem-posing skills by investigating their ability to associate linear graphs with daily life situations. Prospective teachers were given linear graphs and asked to pose problems that could potentially be represented by the graphs. Their answers were analyzed in two stages. In…
Formation of mutagens in cooked foods. I. Beef.

PubMed

Spingarn, N E; Weisburger, J H

1979-09-01

Mutagens detectable by Salmonella typhimurium TA98, after activation by liver S-9 fraction, are formed when meat is cooked by frying, broiling and boiling. High levels of mutagenic activity are formed rapidly when frying, or more slowly during broiling. Formation of mutagens in boiled beef stock requires several days under reflux, but shows a strong concentration dependence. Time curves suggest that a period exists during which mutagens are not readily formed; however, after this period mutagen production is rapid. Hamburgers from commercial franchises were frequently mutagenically active.
Mighty Mathematicians: Using Problem Posing and Problem Solving to Develop Mathematical Power

ERIC Educational Resources Information Center

McGatha, Maggie B.; Sheffield, Linda J.

2006-01-01

This article describes a year-long professional development institute combined with a summer camp for students. Both were designed to help teachers and students develop their problem-solving and problem-posing abilities.
Nonmutagenicity of betel leaf and its antimutagenic action against environmental mutagens.

PubMed

Nagabhushan, M; Amonkar, A J; D'Souza, A V; Bhide, S V

1987-01-01

Betel leaf (Piper betel) water and acetone extract are nonmutagenic in S. typhimurium strains with and without S9 mix. Both the extracts suppress the mutagenicity of betel quid mutagens in a dose dependent manner. Moreover both the extracts of betel leaf reduce the mutagenicity of benzo(a)pyrene and dimethylbenzanthracene. Acetone extract is more potent than water extract in inhibiting mutagenicity of environmental mutagens.
Structure-Activity Relationship Models for Rat Carcinogenesis and Assessing the Role Mutagens Play in Model Predictivity

PubMed Central

Carrasquer, C. Alex; Batey, Kaylind; Qamar, Shahid; Cunningham, Albert R.; Cunningham, Suzanne L.

2016-01-01

We previously demonstrated that fragment based cat-SAR carcinogenesis models consisting solely of mutagenic or non-mutagenic carcinogens varied greatly in terms of their predictive accuracy. This led us to investigate how well the rat cancer cat-SAR model predicted mutagens and non-mutagens in their learning set. Four rat cancer cat-SAR models were developed: Complete Rat, Transgender Rat, Male Rat, and Female Rat, with leave-one-out (LOO) validation concordance values of 69%, 74%, 67%, and 73%, respectively. The mutagenic carcinogens produced concordance values in the range of 69–76% as compared to only 47–53% for non-mutagenic carcinogens. As a surrogate for mutagenicity comparisons between single site and multiple site carcinogen SAR models was analyzed. The LOO concordance values for models consisting of 1-site, 2-site, and 4+-site carcinogens were 66%, 71%, and 79%, respectively. As expected, the proportion of mutagens to non-mutagens also increased, rising from 54% for 1-site to 80% for 4+-site carcinogens. This study demonstrates that mutagenic chemicals, in both SAR learning sets and test sets, are influential in assessing model accuracy. This suggests that SAR models for carcinogens may require a two-step process in which mutagenicity is first determined before carcinogenicity can be accurately predicted. PMID:24697549
Silver Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review

USGS Publications Warehouse

Eisler, R.

1996-01-01

Ecological and toxicological aspects of silver (Ag) in the environment are briefly summarized with an emphasis on natural resources. Elevated silver concentrations in biota occur in the vicinities of sewage outfalls, electroplating plants, mine waste sites, and silver-iodide seeded areas; in the United States, the photography industry is the major source of anthropogenic silver discharges into the biosphere. Silver and its compounds are not known to be mutagenic, teratogenic, or carcinogenic. Under normal routes of exposure, silver does not pose serious environmental health problems to humans at less than 50.0 ug total Ag/L drinking water or 10.0 ug per cubic meter air. Free silver ion, however, was lethal to representative species of sensitive aquatic plants, invertebrates, and teleosts at nominal water concentrations of 1.2 to 4.9 ug/L; sublethal effects were significant between 0.17 and 0.6 ug/L. Silver was harmful to poultry at concentrations as low as 1.8 mg total Ag/kg whole egg fresh weight by way of injection, 100.0 mg total Ag/L in drinking water, or 200.0 mg total Ag/kg in diets; sensitive mammals were adversely affected at total silver concentrations as low as 250.0 ug/L in drinking water, 6.0 mg/kg in diets, or 13.9 mg/kg whole body.
An Analysis of Problem-Posing Tasks in Chinese and US Elementary Mathematics Textbooks

ERIC Educational Resources Information Center

Cai, Jinfa; Jiang, Chunlian

2017-01-01

This paper reports on 2 studies that examine how mathematical problem posing is integrated in Chinese and US elementary mathematics textbooks. Study 1 involved a historical analysis of the problem-posing (PP) tasks in 3 editions of the most widely used elementary mathematics textbook series published by People's Education Press in China over 3…
Fraction Multiplication and Division Word Problems Posed by Different Years of Pre-Service Elementary Mathematics Teachers

ERIC Educational Resources Information Center

Aydogdu Iskenderoglu, Tuba

2018-01-01

It is important for pre-service teachers to know the conceptual difficulties they have experienced regarding the concepts of multiplication and division in fractions and problem posing is a way to learn these conceptual difficulties. Problem posing is a synthetic activity that fundamentally has multiple answers. The purpose of this study is to…
Generalizability Theory Research on Developing a Scoring Rubric to Assess Primary School Students' Problem Posing Skills

ERIC Educational Resources Information Center

Cankoy, Osman; Özder, Hasan

2017-01-01

The aim of this study is to develop a scoring rubric to assess primary school students' problem posing skills. The rubric including five dimensions namely solvability, reasonability, mathematical structure, context and language was used. The raters scored the students' problem posing skills both with and without the scoring rubric to test the…
An Investigation of Relationships between Students' Mathematical Problem-Posing Abilities and Their Mathematical Content Knowledge

ERIC Educational Resources Information Center

Van Harpen, Xianwei Y.; Presmeg, Norma C.

2013-01-01

The importance of students' problem-posing abilities in mathematics has been emphasized in the K-12 curricula in the USA and China. There are claims that problem-posing activities are helpful in developing creative approaches to mathematics. At the same time, there are also claims that students' mathematical content knowledge could be highly…
An Investigation of Eighth Grade Students' Problem Posing Skills (Turkey Sample)

ERIC Educational Resources Information Center

Arikan, Elif Esra; Ünal, Hasan

2015-01-01

To pose a problem refers to the creative activity for mathematics education. The purpose of the study was to explore the eighth grade students' problem posing ability. Three learning domains such as requiring four operations, fractions and geometry were chosen for this reason. There were two classes which were coded as class A and class B. Class A…
Mathematical Creative Process Wallas Model in Students Problem Posing with Lesson Study Approach

ERIC Educational Resources Information Center

Nuha, Muhammad 'Azmi; Waluya, S. B.; Junaedi, Iwan

2018-01-01

Creative thinking is very important in the modern era so that it should be improved by doing efforts such as making a lesson that train students to pose their own problems. The purposes of this research are (1) to give an initial description of students about mathematical creative thinking level in Problem Posing Model with Lesson Study approach…
Problem Posing with Realistic Mathematics Education Approach in Geometry Learning

NASA Astrophysics Data System (ADS)

Mahendra, R.; Slamet, I.; Budiyono

2017-09-01

One of the difficulties of students in the learning of geometry is on the subject of plane that requires students to understand the abstract matter. The aim of this research is to determine the effect of Problem Posing learning model with Realistic Mathematics Education Approach in geometry learning. This quasi experimental research was conducted in one of the junior high schools in Karanganyar, Indonesia. The sample was taken using stratified cluster random sampling technique. The results of this research indicate that the model of Problem Posing learning with Realistic Mathematics Education Approach can improve students’ conceptual understanding significantly in geometry learning especially on plane topics. It is because students on the application of Problem Posing with Realistic Mathematics Education Approach are become to be active in constructing their knowledge, proposing, and problem solving in realistic, so it easier for students to understand concepts and solve the problems. Therefore, the model of Problem Posing learning with Realistic Mathematics Education Approach is appropriately applied in mathematics learning especially on geometry material. Furthermore, the impact can improve student achievement.

Mutagenicity of heated sugar-casein systems: effect of the Maillard reaction.

PubMed

Brands, C M; Alink, G M; van Boekel, M A; Jongen, W M

2000-06-01

The formation of mutagens after the heating of sugar-casein model systems at 120 degrees C was examined by the Ames test, using Salmonella typhimurium strain TA100. Several sugars (glucose, fructose, galactose, tagatose, lactose, and lactulose) were compared in their mutagenicities. Mutagenicity could be fully ascribed to Maillard reaction products and strongly varied with the kind of sugar. The differences in mutagenicity among the sugar-casein systems were caused by a difference in reaction rate and a difference in reaction mechanism. Sugars with a comparable reaction mechanism (glucose and galactose) showed a higher mutagenic activity corresponding with a higher Maillard reactivity. Disaccharides showed no mutagenic activity (lactose) or a lower mutagenic activity (lactulose) than their corresponding monosaccharides. Ketose sugars (fructose and tagatose) showed a remarkably higher mutagenicity compared with their aldose isomers (glucose and galactose), which was due to a difference in reaction mechanism.
Identification of mutagenic transformation products generated during oxidation of 3-methyl-4-nitrophenol solutions by orbitrap tandem mass spectrometry and quantitative structure-activity relationship analyses.

PubMed

Matsushita, Taku; Honda, Shiho; Kuriyama, Taisuke; Fujita, Yuki; Kondo, Takashi; Matsui, Yoshihiko; Shirasaki, Nobutaka; Takanashi, Hirokazu; Kameya, Takashi

2018-02-01

We used Ames assays to investigate the effects of ozonation (designated O 3 ), ozonation followed by chlorination (O 3 /Cl), an advanced oxidation process (AOP, UV/H 2 O 2 ), and AOP followed by chlorination (AOP/Cl) on the mutagenicity of solutions of 3-methyl-4-nitrophenol (3M4NP), a major environmental degradation product of the organophosphorus insecticide fenitrothion. Whereas O 3 did not induce mutagenicity, O 3 /Cl, AOP, and AOP/Cl converted 3M4NP into mutagenic transformation products (TPs). Using liquid chromatography-mass spectrometry, we detected a total of 138 peaks in the solutions subjected to O 3 /Cl, AOP, and AOP/Cl. To elucidate the TPs responsible for the observed mutagenicity, we performed simple regression analyses of the relationship between the area of each peak and the observed mutagenicity of samples withdrawn periodically during each oxidation process. The area of each of 10 peaks was found to be positively correlated (r 2 ≥ 0.8) with the observed mutagenicity, suggesting that the TPs corresponding to these peaks contributed to the mutagenicity. After taking into account the consistency of mutagenicity induction by the oxidation processes and analyzing the peaks by tandem mass spectrometry, we identified 3 TPs, corresponding to 6 peaks, as candidate mutagens. These TPs were assessed by means of 4 quantitative structure-activity relationship (QSAR) models, and all 3 were predicted to be mutagenic by at least one model. This result was consistent with our assumption that these TPs were mutagens. Ames assays of an authentic sample of one of the 3 TPs revealed that it did not contribute to the mutagenicity. This left 3-methoxy-4-nitrophenol and 2-[(E)-[(2,5-dihydroxyphenyl) methylidene]amino]-5-dihydroxybenzaldehyde on the list of mutagens suspected of contributing to the mutagenicity induced by AOP. No TPs were identified as candidate mutagens responsible for the mutagenicity induced by O 3 /Cl and AOP/Cl. Copyright © 2017 Elsevier Ltd. All rights reserved.
Mutagenicity of particle emissions from solid fuel cookstoves: A literature review and research perspective.

PubMed

Shen, Guofeng

2017-07-01

Household solid fuel use is a major source of many air pollutants causing severe air pollution and adverse health outcomes. In evaluation of health impacts of household air pollution, it is essential to characterize toxic properties like mutagenicity of residential fuel combustion emissions and exposure assessments. Mutagenicity of emissions from solid fuel cookstoves were analyzed through a literature review. T98 and TA100 strains are two most widely used strains in mutagenic Ames test, and results for these two strains are generally positively correlated though they have different endpoints. Direct and indirect mutagenic activities are positively correlated, and statistically insignificantly different though indirect mutagenic emissions are apparently higher. Mutagenicity emission factors on the basis of fuel energy (MJ) or useful energy delivered (MJd) for solid fuel cookstoves vary in nearly 3 orders of magnitude, ranging from 3.0×10 4 rev./MJd to 1.8×10 7 rev./MJd (or 1.1×10 4 rev./MJ to 4.2×10 6 rev./MJ). Low mutagenic emissions are reported for high efficiency stoves such as a forced-draft one. Mutagenicity emission factors are positively correlated with emissions of PM 2.5 . Relationship between mutagenicity and polycyclic aromatic hydrocarbons (PAHs) emissions is inconsistent among studies as PAHs are minor fractions of toxic organics contributing to the total mutagenicity. Generally, studies on mutagenicity of emissions from household cookstoves are very limited, and future studies are encouraged on mutagenic emissions from different fuel types and household stoves, evaluation of mutagenic activities of both gaseous and particulate emissions, and toxicology and exposure assessments of household air pollution. Copyright © 2017 Elsevier Inc. All rights reserved.
Assessment of the Mutagenicity of Sediments from Yangtze River Estuary Using Salmonella Typhimurium/Microsome Assay

PubMed Central

Liu, Li; Chen, Ling; Floehr, Tilman; Xiao, Hongxia; Bluhm, Kerstin; Hollert, Henner; Wu, Lingling

2015-01-01

Sediments in estuaries are of important environmental concern because they may act as pollution sinks and sources to the overlying water body. These sediments can be accumulated by benthic organisms. This study assessed the mutagenic potential of sediment extracts from the Yangtze River estuary by using the Ames fluctuation assay with the Salmonella typhimurium his (−) strain TA98 (frameshift mutagen indicator) and TA100 (baseshift mutagen indicator). Most of the sediment samples were mutagenic to the strain TA98, regardless of the presence or absence of exogenous metabolic activation (S9 induction by β-naphthoflavone/phenobarbital). However, none of the samples were mutagenic to the strain TA100. Thus, the mutagenicity pattern was mainly frameshift mutation, and the responsible toxicants were both direct (without S9 mix) and indirect (with S9 mix) mutagens. The mutagenicity of the sediment extracts increased when S9 was added. Chemical analysis showed a poor correlation between the content of priority polycyclic aromatic hydrocarbons and the detected mutagenicity in each sample. The concept of effect-directed analysis was used to analyze possible compounds responsible for the detected mutagenic effects. With regard to the mutagenicity of sediment fractions, non-polar compounds as well as weakly and moderately polar compounds played a main role. Further investigations should be conducted to identify the responsible components. PMID:26606056
Investigations on genotoxic effects of groundwater from the Mitterndorfer Senke and from the vicinity of Wiener Neustadt.

PubMed

Knasmüller, S; Helma, C; Eckl, P M; Gottmann, E; Steinkellner, H; Kassie, F; Haider, T; Parzefall, W; Schulte-Hermann, R

1998-12-11

This report describes the first study on genotoxic effects of Austrian ground- and drinking waters. Samples from the Mitterndorfer Senke (MS) and the vicinity of Wiener Neustadt were tested over a three years period. The MS is the largest aquifer in Austria. Due to deposition of industrial and community wastes, chemicals have polluted the groundwater in this area. Aim of the present study was to elucidate if consumption of these waters might pose a carcinogenic risk to humans. 43 Water samples were tested in a test battery which consisted of bacterial gene mutation assays (Salmonella strains TA100 and TA98), micronucleus (MN) assays with cultures of primary rat hepatocytes and plant bioassays (MN tests with Tradescantia and Vicia faba). For the bacterial assays, the water samples were extracted with XAD resins. In total, 27.9% of the samples caused positive effects; 8 samples were active in Salmonella microsome assays, Strain TA100 was particularly sensitive upon addition of metabolic activation mix (6 positive samples). Four samples were positive exclusively in MN assays with cultures of primary rat hepatocytes; one sample gave positive results in all three bioassays. Finished waters from waterworks were consistently devoid of mutagenic activity under all experimental conditions. Overall, only a small fraction of the groundwaters caused mutagenic effects and in all cases the activities were moderate. Comparison of the results of the present study with data obtained in other investigations under similar experimental conditions shows that the genotoxicity of groundwaters of the MS area are lower than the effects caused by ground- and drinking waters from other countries. The fact that no genotoxic activity was detected in any of the finished drinking waters can be taken as an indication that consumption of these waters does not pose a health hazard arising from contamination with genotoxic carcinogens to humans.
Induction of Abasic Sites by the Drinking-Water Mutagen MX in Salmonella TA100

EPA Science Inventory

Mutagen X (MX) is a chlorinated furanone that accounts for more of the mutagenic activity of drinking water than any other disinfection by-product. It is one of the most potent base-substitution mutagens in the Salmonella (Ames) mutagenicity assay, producing primarily GC to TA mu...
Mutagenicity of chalks. A case in which the test results led to the improvement of the quality of commercial goods.

PubMed

Hayatsu, H; Ohara, Y; Hayatsu, T; Togawa, K

1983-10-01

Mutagenicity testing, of methanolic extracts of chalks, by the Salmonella/mammalian-microsome system revealed that the blue and the green chalks contained mutagens. A positive mutagenic response was observed on Salmonella typhimurium strain TA98, both in the presence and absence of the microsome system (S9). The source of the mutagenicity was traced to the blue pigment used for manufacturing these chalks. The pigment, copper phthalocyanine, a product of a Japanese chemical industrial company, was found to contain impurities that were mutagenic. The mutagenic principle giving positive response in the TA98 in the presence of S9 was purified 10(5)-fold from the original pigment. Although its structure is yet to be elucidated, this indirect frame-shift mutagen had a strong activity: 5700 His+ revertants per microgram. This information, delivered in the beginning of 1981, prompted the manufacturer to start supplying a mutagen-free product. As a result, the blue chalks on the market became no longer mutagenic in the summer of 1982.
Problem Posing and Solving with Mathematical Modeling

ERIC Educational Resources Information Center

English, Lyn D.; Fox, Jillian L.; Watters, James J.

2005-01-01

Mathematical modeling is explored as both problem posing and problem solving from two perspectives, that of the child and the teacher. Mathematical modeling provides rich learning experiences for elementary school children and their teachers.
Volatilization of mutagens from beef during cooking.

PubMed

Rappaport, S M; McCartney, M C; Wei, E T

1979-12-01

The process of cooking beef substances which are mutagenic in the Ames Salmonella/microsome bioassay [1,2]. In this study, the formation and disposition of basic mutagens produced by cooking beef at different temperatures were examined. Mutagenic activity increased exponentially with cooking temperature between 137 degrees C and 252 degrees C. However, the amount of mutagenic activity remaining in the meat was only 1--7% of that which was volatilized into the air. The ingested dose of mutagens may therefore be significantly influenced by factors which restrict the dissipation of mutagens from the container, as well as by cooking temperature. Inhalation of airborne mutagens from cooking, as an alternative route of exposure, should be investigated when considered in light of some epidemiological data showing an excess of lung and bladder cancer among cooks and kitchen workers.
Mutagenicity of benzotrichloride and related compounds.

PubMed

Yasuo, K; Fujimoto, S; Katoh, M; Kikuchi, Y; Kada, T

1978-11-01

Benzotrichloride (BTC), benzal chloride (BDC), benzyl chloride (BC) and benzoyl chloride (BOC) were surveyed for their mutagenicity in microbial systems such as rec-assay using Bacillus subtilis and reversion assays using E. coli WP2 and Ames Salmonella TA strains with or without metabolic activation in vitro. BTC and BDC required metabolic activation for their mutagenic activities in several strains of E. coli and Salmonella. The mutagenic metabolites of these compounds may not have been produced by hydrolysis. BC was weakly mutagenic without metabolic activation. Only BOC exhibited no mutagenic activity in the detection procedures used. The mutagenic metabolite of BTC might be very unstable under our experimental conditions. The strain E. coli WP2 try hcr was more sensitive than E. coli B/r WP2 try (hcr+) with regard to the mutagenicity of BTC.
Mutagenic activity of south Indian food items.

PubMed

Sivaswamy, S N; Balachandran, B; Balanehru, S; Sivaramakrishnan, V M

1991-08-01

Dietary components and food dishes commonly consumed in South India were screened for their mutagenic activity. Kesari powder, calamus oil, palm drink, toddy and Kewra essence were found to be strongly mutagenic; garlic, palm oil, arrack, onion and pyrolysed portions of bread toast, chicory powder were weakly mutagenic, while tamarind and turmeric were not. Certain salted, sundried and oil fried food items were also mutagenic. Cissus quadrangularis was mutagenic, while 'decoctions' of cumin seeds, aniseeds and ginger were not. Several perfumes, essential oils and colouring agents, which are commonly used were also screened and many of them exhibited their mutagenic potential by inducing the 'reverse mutation' in Salmonella typhimurium tester strains.
Mutagenic activity of disinfection by-products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cognet, L.; Courtois, Y.; Mallevialle, J.

1986-11-01

Data on raw water quality, disinfection treatment practices, and the resulting mutagenic properties of the treated water were compiled from pilot- and full-scale treatment experiments to evaluate that parameter which might produce variability in the results of a mutagenic study. Analysis of the data and comparison of treatment practices indicated that the measured mutagenic activity is strongly related to the characteristics of the organic matter in the raw water, the methodology used to sample and detect mutagens, the scale of the study both in terms of treatment flow and period of study, and the point at which and the conditionsmore » under which oxidants are added during treatment. Conclusions regarding disinfection systems in full-scale water treatment plants include the following: When raw water is pretreated and high concentrations of organics are present in the raw water, both ozonation and chlorination increased mutagenic activity. However, no significant difference in mutagenicity was found between the two oxidants. Both in the case of a nitrified groundwater and a clarified surface water, the mutagenic activity of the water after ozonation was related to its mutagenic activity before ozonation. With ozonation, mutagenic activity decreased after granular activated carbon (GAC) filtration. Thus, when GAC filtration follows ozone disinfection, early addition of oxidants may not be deleterious to the finished water quality. When chlorine or chlorine dioxide is added after GAC filtration, chlorine dioxide was found to produce a less mutagenic water than chlorine. Although these conclusions suggest means of controlling mutagenic activity during treatment, it must be stressed that the measurement of mutagenicity is a presumptive index of contamination level.« less
A mutant screening method by critical annealing temperature-PCR for site-directed mutagenesis.

PubMed

Liu, Ying; Wu, Ting; Song, Jian; Chen, Xuelian; Zhang, Yu; Wan, Yu

2013-03-11

Distinguishing desired mutants from parental templates and undesired mutants is a problem not well solved in Quikchange™ mutagenesis. Although Dpn I digestion can eliminate methylated parental (WT) DNA, the efficiency is not satisfying due to the existence of hemi-methylated DNA in the PCR products, which is resistant to Dpn I. The present study designed a novel critical annealing temperature (T(c))-PCR to replace Dpn I digestion for more perfect mutant distinguishing, in which part-overlapping primers containing mutation(s) were used to reduce initial concentration of template DNA in mutagenic PCR. A T(c)-PCR with the same mutagenic primers was performed without Dpn I digestion. The T(c) for each pair of the primers was identified by gradient PCR. The relationship between PCR-identified T(c) and T(m) of the primers was analyzed and modeled with correlation and regression. Gradient PCR identified a T(c) for each of 14 tested mutagenic primers, which could discriminate mismatched parental molecules and undesired mutants from desired mutants. The PCR-identified T(c) was correlated to the primer's T(m) (r = 0.804, P<0.0001). Thus, in practical applications, the T(c) can be easily calculated with a regression equation, T(c)= 48.81 + 0.253*T(m). The new protocol introduced a novel T(c)-PCR method for mutant screening which can more efficiently and accurately select against parental molecules and undesired mutations in mutagenic sequence segments.
Problem-posing in education: transformation of the practice of the health professional.

PubMed

Casagrande, L D; Caron-Ruffino, M; Rodrigues, R A; Vendrúsculo, D M; Takayanagui, A M; Zago, M M; Mendes, M D

1998-02-01

This study was developed by a group of professionals from different areas (nurses and educators) concerned with health education. It proposes the use of a problem-posing model for the transformation of professional practice. The concept and functions of the model and their relationships with the educative practice of health professionals are discussed. The model of problem-posing education is presented (compared to traditional, "banking" education), and four innovative experiences of teaching-learning are reported based on this model. These experiences, carried out in areas of environmental and occupational health and patient education have shown the applicability of the problem-posing model to the practice of the health professional, allowing transformation.
[The hygienic evaluation of the mutagenic potential of industrial wastes].

PubMed

Zhurkov, V S; Rusakov, N V; Tonkopiĭ, N I; Sycheva, L P; Akhal'tseva, L V; Neiaskina, E V; Pirtakhiia, N V; Malysheva, A G; Rastiannikov, E G

1998-01-01

A combination of two approaches to assessing the carcinogenic and mutagenic potentials of industrial waste is proposed. One approach includes determination of the carcinogenic and mutagenic properties of individual chemicals of waste, the other involves biological indication of the cumulative mutagenic activity of waste samples. The mutagenic potential of some waste samples of aircraft industry was determined.
Mutagenicity of adsorbates to a copper-phthalocyanine derivative recovered from municipal river water.

PubMed

Sayato, Y; Nakamuro, K; Ueno, H; Goto, R

1990-12-01

Blue cotton, bearing a covalently bound copper-phthalocyanine derivative capable of adsorbing polycyclic aromatic hydrocarbons (PAHs) over 3 rings, was applied to recover mutagens from the Katsura River which is a tributary of the Yodo River. The Ames Salmonella/microsome assay with TA98 and TA100 of the blue cotton concentrate recovered from the river water demonstrated indirect mutagenicity toward TA98. The subfractions separated by Sephadex G-25 gel chromatography also showed direct mutagenicity in strains YG1021 and YG1024, the nitroreductase- and O-acetyltransferase-overproducing derivatives of TA98; this activity was greatly increased by the addition of S9 mix, especially in YG1024. However, these subfractions were less mutagenic with TA98NR or TA98/1,8-DNP6, regardless of whether S9 mix was present or not. The behaviors of these mutagenic activities therefore suggested that frameshift mutagens of both directly mutagenic nitroarenes and indirectly mutagenic aminoarenes were present in the blue cotton concentrate from the river water.
Mutagenic screening of diamine monomers

NASA Technical Reports Server (NTRS)

Ross, W. D.; Noble, J. E.; Gridley, J. A.; Fullenkamp, J. M.; Wininger, M. T.; Graham, J. A.

1983-01-01

The effects of phenyl ring coupling moieties, of isomeric amine positions relative to the coupling groups, and of insertion of other coupling groups on the mutagenic response of a series of dianilines were investigated using the Ames Salmonella assay. Generally, S-9 metabolic activation from Aroclor-induced rat liver was required for mutagenic expression. The range of mutagenicity of steric isomers of several dianiline series was also investigated. No mutagenicity was found for purified samples of o,o' and m,p' isomers of methylene dianiline (MDA) and diaminobenzophenone, while varying degrees of mutagenicity were found for other isomers. The mutagenicity of "benzylogs" of MDA decreased as the degree of linear separation of the m,m' anilino groups by aromatic rings increased. Methylation and two-year storage increased mutagenic response in certain isomers of MDA. However, high performance liquid chromatography indicated there was no discernible change in m,p'-MDA samples aged under varied conditions over four months. Likewise, no change in mutagenicity was found.
[Problem-posing as a nutritional education strategy with obese teenagers].

PubMed

Rodrigues, Erika Marafon; Boog, Maria Cristina Faber

2006-05-01

Obesity is a public health issue with relevant social determinants in its etiology and where interventions with teenagers encounter complex biopsychological conditions. This study evaluated intervention in nutritional education through a problem-posing approach with 22 obese teenagers, treated collectively and individually for eight months. Speech acts were collected through the use of word cards, observer recording, and tape-recording. The study adopted a qualitative methodology, and the approach involved content analysis. Problem-posing facilitated changes in eating behavior, triggering reflections on nutritional practices, family circumstances, social stigma, interaction with health professionals, and religion. Teenagers under individual care posed problems more effectively in relation to eating, while those under collective care posed problems in relation to family and psychological issues, with effective qualitative eating changes in both groups. The intervention helped teenagers understand their life history and determinants of eating behaviors, spontaneously implementing eating changes and making them aware of possibilities for maintaining the new practices and autonomously exercising their role as protagonists in their own health care.
Chemistry of mutagens and carcinogens in broiled food.

PubMed Central

Nishimura, S

1986-01-01

From a chemical point of view, the following subjects are important areas in studies on mutagens and carcinogens in broiled foods. In addition to heterocyclic amines which need microsomal activation, the structural elucidation of more labile direct-acting mutagens is necessary. It is known that there are still various unknown minor mutagens in broiled foods. Although the structural characterization of such compounds is more difficult, it is important since they might be hazardous in spite of their low mutagenicity. A more feasible and easier method for quantitative analysis of mutagens, in addition to HPLC and GC/MS methods presently employed, must be developed. The mechanism of formation of mutagens by broiling of food should be studied. An effective chemical method to prevent formation of mutagens or to destroy them, once formed, should be developed. PMID:3757944
Fostering Mathematical Creativity through Problem Posing and Modeling Using Dynamic Geometry: Viviani's Problem in the Classroom

ERIC Educational Resources Information Center

Contreras, José N.

2013-01-01

This paper discusses a classroom experience in which a group of prospective secondary mathematics teachers were asked to create, cooperatively (in class) and individually, problems related to Viviani's problem using a problem-posing framework. When appropriate, students used Sketchpad to explore the problem to better understand its attributes…

A comparison of methods for concentrating mutagens in drinking water--recovery aspects and their implications for the chemical character of major unidentified mutagens.

PubMed

Wigilius, B; Borén, H; Carlberg, G E; Grimvall, A; Möller, M

1985-12-01

A comparison of techniques for concentrating mutagenic compounds in drinking water has shown that XAD-2 adsorption and dichloromethane extraction have acceptable and almost identical enrichment properties, while purging at an elevated temperature is inappropriate in this context. Quantitatively, the most important drinking water mutagens could only be adsorbed (extracted) after acidification of the water, and even then recovery was far from complete. Recovery experiments with known mutagens from pulp mill effluents have shown that none of the major chlorination-stage mutagens identified thus far can explain the mutagenic activity of extracts from neutral or acidified chlorinated drinking water.
Hair dyes are mutagenic: identification of a variety of mutagenic ingredients.

PubMed Central

Ames, B N; Kammen, H O; Yamasaki, E

1975-01-01

We have previously described a sensitive bacterial test for dectecting carcinogens as mutagens. We have previously described a sensitive bacterial test for detecting carcinogens as mutagens. We show here that 89% (150/169) of commercial oxidative-type (hydrogen peroxide) hair dye formulations are mutagenic in this test. Of the 18 components of these hair dyes, nine show various degrees of mutagenicity:2,4-diaminoanisole, 4-nitro-o-phenylenediamine, 2-nitro-p-phenylenediamine, 2,5-diaminoanisole, 2-amino-5-nitrophenol, m-phenylenediamine, o-phenylenediamine, 2-amino-4-nitrophenol, and 2,5-diaminotoluene. Three hair dye components (p-phenylenediamine, 2,5-diaminotuluene, and 2,5-diaminoanisole) become strongly mutagenic after oxidation by H2O2: the mutagenic product of p-phenylenediamine is identified as the known trimer, Bandrowski's base. 2,4-Diaminotoluene, a hair dye component until recently, is also shown to be mutagenic: this compound has been shown to be a carcinogen in rats and is used in large amounts in the polyurethane foam industry. About 20,000,000 people (mostly women) dye their hair in the U.S. and the hazard could be considerable if these chemicals are actually mutagenic and carcinogenic in humans. Images PMID:1094469
Mutagenicity of fume particles from stainless steel welding.

PubMed

Hedenstedt, A; Jenssen, D; Lidestein B-M; Ramel, C; Rannug, U; Stern, R M

1977-12-01

Welding fume particles collected from different welding procedures were tested for mutagenicity in Escherichia coli, with the inhibition zone in pol A- as compared to pol A+, and in Salmonella typhimurium, TA 100 strain. While no mutagenicity was found with mild steel welding, a mutagenic effect was established with samples from stainless steel welding. This mutagenicity was particularly associated with manual metal arc (MMA) welding, and less so with metal inert-gas welding. A decrease in or an elimination of the effect occurred with a liver microsomal metabolizing system (S-9 mix). The MMA samples produced the strongest mutagenic effect. More-detailed investigations on these samples showed that the mutagenic agent(s) is water soluble. An increased mutagenicity, which also revealed the induction of frame shift mutations, was found with TA 98. The same welding fume sample was used for a mutagenicity test (resistance to 6-thioguanine) with V 79 hamster cells. Because of the high toxicity of these welding fume particles on the cells, only very low concentrations could be tested, but the increase of mutations, when compared to the negative control, was significant. It is suggested that hexavalent chromium may be involved in the mutagenic effect of the welding fumes.
Past, present, and future of mutagens in cooked foods.

PubMed

Sugimura, T

1986-08-01

Mutation assay with Salmonella typhimurium enabled us to detect various types of mutagens in cooked foods. A series of mutagenic heterocyclic amines has been isolated and identified in broiled fish and meat and in pyrolyzates of amino acids and proteins. Feeding experiments showed these mutagens to be carcinogenic in mice and rats. The mechanism of formation and pathway of metabolic activation of these heterocyclic amines have been elucidated. Their contents in various cooked foods have been determined. The presence of mutagenic nitropyrenes (some of which were confirmed as carcinogens) in grilled chicken was also established. Roasted coffee beans also yield mutagens such as methylglyoxal. The formation of mutagen precursors, including beta-carboline derivatives and tyramine which become mutagens with nitrite treatment, was found during food processing. Oncogene activation in animal tumors induced by some of these food mutagens/carcinogens has been confirmed. The role of mutagens/carcinogens in cooked foods in human cancer development has not yet been exactly evaluated. In order to do this, more information on their carcinogenic potency, human intake, metabolism in the human body, and the effects of combined administration with other initiators, promoters and other modifying factors in food is required.
Exposure to mutagenic chemicals in foundry and urban environments.

PubMed

Barański, B; Palus, J; Janik-Spiechowicz, E

1989-01-01

The study was aimed at the estimation of occupational exposure to mutagenic substances in a piston-ring foundry. The following samples were examined: solid phase of aerosol from the foundry and from different places of urban environment together with the foundry workers' urine collected during the 8-hour shift. The mutagenic substances were extracted from the collected material with acetone or concentrated with XAD-2 resin. The mutagenic property was estimated with the Ames' test using S. typhimurium strain TA98 without and with S9 fraction. The highest mutagenic activity was found at the following work-posts: caster, moulder, steerer of an induction furnace, and smelter and in the office rooms and in the flat occupied by heavy smokers. The mutagenic activity of aerosol at some other productive workposts in the foundry was similar to the mutagenic activity of aerosol in the office and flat rooms occupied by nonsmokers or in the street in Lodz. The mutagenic activity of urine from foundry workers was not correlated with the level of the occupational inhalation exposure to the mutagenic substances, however, the mutagenic activity of urine from smoking workers was about 10-20 times higher than from nonsmokers.
Investigating Mathematics Teachers Candidates' Knowledge about Problem Solving Strategies through Problem Posing

ERIC Educational Resources Information Center

Ünlü, Melihan

2017-01-01

The aim of the study was to determine mathematics teacher candidates' knowledge about problem solving strategies through problem posing. This qualitative research was conducted with 95 mathematics teacher candidates studying at education faculty of a public university during the first term of the 2015-2016 academic year in Turkey. Problem Posing…
Mutagens in urine of non-smoking and smoking workers in an aircraft tyre retreading plant. Skin exposure as a causal factor?

PubMed

Bos, R P; Kromhout, H; Ikink, H; de Haan, W; Koppejan, J; Theuws, J L

1989-05-01

In an aircraft type retreading plant environmental samples taken at several departments showed mutagenic properties. Thursday urine samples of non-smoking and smoking workers showed higher urinary mutagenicity than urine samples collected on Sundays, thus suggesting occupational exposure to mutagenic substances. A relation between urinary mutagenicity on Thursdays and skin contamination measured on Wednesdays was observed. The data suggest that intake through the skin plays an important role in the occupational exposure to mutagenic compounds of rubber workers.
Antigenotoxic effects of Citrus aurentium L. fruit peel oil on mutagenicity of two alkylating agents and two metals in the Drosophila wing spot test.

PubMed

Demir, Eşref; Kocaoğlu, Serap; Cetin, Huseyin; Kaya, Bülent

2009-07-01

Antigenotoxic effects of Citrus aurentium L. (Rutaceae) fruit peel oil (CPO) in combination with mutagenic metals and alkylating agents were studied using the wing spot test of D. melanogaster. The four reference mutagens, potassium dichromate (K2Cr2O7), cobalt chloride (CoCl2), ethylmethanesulfonate (EMS), and N-ethyl-N-nitrosourea (ENU) were clearly genotoxic. CPO alone at doses from 0.1 to 0.5% in Tween 80 was not mutagenic and did not enhance the mutagenic effect of the reference mutagens. However, antigenotoxic effects of CPO were clearly demonstrated in chronic cotreatments with mutagens and oil, by a significant decrease in wing spots induced by all four mutagens. The D. melanogaster wing spot test was found to be a suitable assay for detecting antigenotoxic effects in vivo. Copyright 2009 Wiley-Liss, Inc.
Health research needed to resolve scientific issues surrounding drinking water disinfection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleffman, D.

Disinfection of drinking water will most likely continue in the United States in order to prevent exposure to microbial pathogens that can cause infectious disease. However, the emergence of concerns over possible toxicological effects, including cancer, mutagenicity, cardiovascular disease, and reproductive effects, may require that the disinfection techniques used in this country be altered or changed. First, the spectrum of possible health effects and the level of risk posed by exposure to chemicals in drinking water must be determined. This will require a continuing research program to develop the scientific data necessary to resolve these issues. In this paper, themore » authors discusses the microbiological, chemical, toxicological, and epidemiological research that is needed to address these issues.« less
Inhibitory effects of neem seed oil and its extract on various direct acting and activation-dependant mutagens-induced bacterial mutagenesis.

PubMed

Vijayan, Vinod; Tiwari, Pramod Kumar; Meshram, Ghansham Pundilikji

2013-12-01

Azadirachta indica A. Juss (Meliaceae), commonly called neem is a plant native to the Indian sub-continent. Neem oil extracted from the seeds of neem tree has shown promising medicinal properties. To investigate the possible anti-mutagenic activity of neem seed oil (NO) and its dimethylsulfoxide (DMSO) extract (NDE) on the mutagenicity induced by various direct acting and activation-dependant mutagens. The possible anti-mutagenic activity of NO (100-10,000 µg/plate) and NDE (0.1-1000 µg/plate) as well as the mechanism of anti-mutagenic activity was studied in an in vitro Ames Salmonella/microsome assay. NSO and NDE inhibited the mutagenic activity of methyl glyoxal (MG), in which case the extent of inhibition ranged from 65 to 77% and against 4-nitroquinoline-N-oxide (NQNO); it showed a 48-87% inhibition in the non-toxic doses. Similar response of NSO and NDE was seen against the activation-dependant mutagens aflatoxin B1 (AFB1, 48-88%), benzo(a)pyrene (B(a)P, 31-85%), cyclophosphamide (CP, 66-71%), 20-methylcholanthrane (20-MC, 37-83%) and acridine orange (AO, 39-72%) in the non-toxic doses. Mechanism-based studies indicated that NDE exhibits better anti-mutagenic activity in the pre- and simultaneous-treatment protocol against MG, suggesting that one or several active phytochemicals present in the extract covalently bind with the mutagen and prevent its interaction with the genome. These findings demonstrate that neem oil is capable of attenuating the mutagenic activity of various direct acting and activation-dependant mutagens.
Analysis of commercial bouillons for trace levels of mutagens.

PubMed

Stavric, B; Matula, T I; Klassen, R; Downie, R H

1993-12-01

A new method, developed specifically for the extraction of heterocyclic aromatic amine (HAA) type mutagens from different food matrices, was applied to various forms of commercially available bouillons. This procedure is based on liquid-liquid extraction of the sample at different pH values. Recovery and reproducibility of the procedure was determined by processing spiked samples using a mutagenicity bioassay technique as an endpoint. The mutagenicity was tested in the Salmonella/microsome assay using strain TA98 with metabolic activation. 22 bouillon samples in liquid, cube or powder forms from seven manufacturers were extracted and tested for potential mutagenicity. The mutagenic activity of these samples varied and ranged from non-detectable to about 1200 induced revertants per gram of solid material, with a median value of approximately 250 revertants/g. The mutagenic response appeared to be dependent on the source rather than the type or form of the product tested. A negative response was obtained from only one chicken bouillon, and the highest positive response was obtained from a beef bouillon in cube form. It appears that the average beef sample, regardless of form, has a higher mutagenic potency than chicken or chicken and turkey samples. Overall, the intake of mutagens from commercial bouillons (obtained as cubes, concentrates or dry mixes) to prepare one serving (as bouillon, soup, casseroles, etc.) is considerably less than that reported in the literature for one serving of fried beef or pork. The extractability and mutagenic characteristics of these samples indicate the presence of HAA-type mutagens. Work is in progress to identify the mutagenic factors in bouillons.
A Problem-Solving Conceptual Framework and Its Implications in Designing Problem-Posing Tasks

ERIC Educational Resources Information Center

Singer, Florence Mihaela; Voica, Cristian

2013-01-01

The links between the mathematical and cognitive models that interact during problem solving are explored with the purpose of developing a reference framework for designing problem-posing tasks. When the process of solving is a successful one, a solver successively changes his/her cognitive stances related to the problem via transformations that…
Opportunities to Pose Problems Using Digital Technology in Problem Solving Environments

ERIC Educational Resources Information Center

Aguilar-Magallón, Daniel Aurelio; Fernández, Willliam Enrique Poveda

2017-01-01

This article reports and analyzes different types of problems that nine students in a Master's Program in Mathematics Education posed during a course on problem solving. What opportunities (affordances) can a dynamic geometry system (GeoGebra) offer to allow in-service and in-training teachers to formulate and solve problems, and what type of…
Physical factors affecting the mutagenicity of fly ash from a coal-fired power plant.

PubMed

Fisher, G L; Chrisp, C E; Raabe, O G

1979-05-25

The two finest, most respirable coal fly ash fractions collected from the smokestack of a power plant were more mutagenic than two coarser fractions. Mutagenicity was evaluated in the histidine-requiring bacterial strains TA 1538, TA 98, and TA 100 of Salmonella typhimurium. Ash samples collected from the hoppers of an electrostatic precipitator in the plant were not mutagenic. The mutagens in coal fly ash were resistant to x-ray or ultraviolet irradiation, possibly as a result of stabilization by fly ash surfaces. All mutagenic activity is lost with heating to 350 degrees C.
Runoff of genotoxic compounds in river basin sediment under the influence of contaminated soils.

PubMed

da Costa, Thatiana Cappi; de Brito, Kelly Cristina Tagliari; Rocha, Jocelita Aparecida Vaz; Leal, Karen Alam; Rodrigues, Maria Lucia Kolowski; Minella, Jean Paolo Gomes; Matsumoto, Silvia Tamie; Vargas, Vera Maria Ferrão

2012-01-01

Contaminated sites must be analyzed as a source of hazardous compounds in the ecosystem. Contaminant mobility in the environment may affect sources of surface and groundwater, elevating potential risks. This study looked at the genotoxic potential of samples from a contaminated site on the banks of the Taquari River, RS, Brazil, where potential environmental problems had been identified (pentachlorophenol, creosote and hydrosalt CCA). Samplers were installed at the site to investigate the drainage material (water and particulate soil matter) collected after significant rainfall events. Organic extracts of this drained material, sediment river samples of the Taquari River (interstitial water and sediment organic extracts) were evaluated by the Salmonella/microsome assay to detect mutagenicity and by Allium cepa bioassays (interstitial water and whole sediment samples) to detect chromosomal alterations. Positive mutagenicity results in the Salmonella/microsome assay of the material exported from the area indicate that contaminant mixtures may have drained into the Taquari River. This was confirmed by the similarity of mutagenic responses (frameshift indirect mutagens) of organic extracts from soil and river sediment exported from the main area under the influence of the contaminated site. The Allium cepa test showed significant results of cytotoxicity, mutagenic index and chromosome aberration in the area under the same influence. However, it also showed the same similarity in positive results at an upstream site, which probably meant different contaminants. Chemical compounds such as PAHs, PCF and chromium, copper and arsenic were present in the runoff of pollutants characteristically found in the area. The strategy employed using the Salmonella/microsome assay to evaluate effects of complex contaminant mixtures, together with information about the main groups of compounds present, allowed the detection of pollutant dispersion routes from the contaminated site to the Taquari River sediment. Copyright Â© 2011 Elsevier Inc. All rights reserved.
Preliminary safety assessment of C-8 xylitol monoester and xylitol phosphate esters.

PubMed

Silveira, J E P S; Pereda, M C V; Nogueira, C; Dieamant, G; Cesar, C K M; Assanome, K M; Silva, M S; Torello, C O; Queiroz, M L S; Eberlin, S

2016-02-01

Most of the cosmetic compounds with preservative properties available in the market pose some risks concerning safety, such as the possibility of causing sensitization. Due to the fact that there are few options, the proper development of new molecules with this purpose is needed. Xylitol is a natural sugar, and the antimicrobial properties of xylitol-derived compounds have already been described in the literature. C-8 xylitol monoester and xylitol phosphate esters may be useful for the development of skincare products. As an initial screen for safety of chemicals, the combination of in silico methods and in vitro testing can aid in prioritizing resources in toxicological investigations while reducing the ethical and monetary costs that are related to animal and human testing. This study was designed to evaluate the safety of C-8 xylitol monoester and xylitol phosphate esters regarding carcinogenicity, mutagenicity, skin and eye irritation/corrosion and sensitization through alternative methods. For the initial safety assessment, quantitative structure-activity relationship methodology was used. The prediction of the parameters carcinogenicity/mutagenicity, skin and eye irritation/corrosion and sensitization was generated from the chemical structure. The analysis also comprised physical-chemical properties, Cramer rules, threshold of toxicological concern and Michael reaction. In silico results of candidate molecules were compared to 19 compounds with preservative properties that are available in the market. Additionally, in vitro tests (Ames test for mutagenicity, cytotoxicity and phototoxicity tests and hen's egg test--chorioallantoic membrane for irritation) were performed to complement the evaluation. In silico evaluation of both molecules presented no structural alerts related to eye and skin irritation, corrosion and sensitization, but some alerts for micronucleus and carcinogenicity were detected. However, by comparison, C-8 xylitol monoester, xylitol phosphate esters showed similar or better results than the compounds available in the market. Concerning experimental data, phototoxicity and mutagenicity results were negative. As expected for compounds with preservative activity, xylitol-derived substances presented positive result in cytotoxicity test. In hen's egg test, both molecules were irritants. Our results suggested that xylitol-derived compounds appear to be suitable candidates for preservative systems in cosmetics. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.
The mutagenicities of safrole, estragole, eugenol, trans-anethole, and some of their known or possible metabolites for Salmonella typhimurium mutants.

PubMed

Swanson, A B; Chambliss, D D; Blomquist, J C; Miller, E C; Miller, J A

1979-04-01

Safrole, estragole, anethole, and eugenol and some of their known or possible metabolites were tested for mutagenic activity for S. typhimurium TA1535, TA100, and TA98. Highly purified 1'-hydroxyestragole and 1'-hydroxysafrole were mutagenic (approximately 15 and 10 revertants/micromole, respectively) for strain TA100 in the absence of fortified liver microsomes; trans-anethole and estragole appeared to have very weak activity. 3'-Hydroxyanethole was too toxic for an adequate test. Supplementation with NADPH-fortified rat-liver microsomes and cytosol converted 3'-hydroxyanethole to a mutagen(s) and increased the mutagenic activities for strain TA100 of 1'-hydroxyestragole, 1'-hydroxysafrole, estragole, and anethole. No mutagenicity was detected for safrole or eugenol with or without added NADPH-fortified liver preparations. The electrophilic 2',3'-oxides of safrole, 1'-hydroxysafrole, 1'-acetoxysafrole, 1'-oxosafrole, estragole, 1'-hydroxyestragole, and eugenol showed dose-dependent mutagenic activities for strain TA1535 in the absence of fortified liver microsomes. These mutagenic activities ranged from about 330 revertants/micromole for 1'-oxosafrole-2',3'-oxide to about 7000 revertants/micromole for safrole-2',3'-oxide. The arylalkenes, their hydroxylated derivatives, or their epoxides did not show mutagenic activity for strain TA98, except for 1'-oxosafrole-2',3'-oxide, which had weak activity. Since the arylalkenes are hydroxylated and/or epoxidized by hepatic microsomes, hydroxy and epoxide derivatives appear to be proximate and ultimate mutagenic metabolites, respectively, of the arylalkenes.
An Integrated View of Air Mutagenicity

EPA Science Inventory

The mutagenic potency of ambient air particulate material (PM) in the Salmonella mutagenicity assay (revertants/mg PM) varies only ~1 order of magnitude worldwide; however, the mutagenic potency of the air itself (revertants/m3 of air) varies ~5 orders of magnitude (IARC Monograp...
Loss of heterocyclic amine mutagens by insoluble hemicellulose fiber and high-molecular-weight soluble polyphenolics of coffee.

PubMed

Kato, T; Takahashi, S; Kikugawa, K

1991-01-01

The presence of 2 kinds of components in brewed and instant coffee that could remove and destroy heterocyclic amine mutagens was demonstrated. The component that could remove the mutagens was insoluble fiber composed of hemicellulose. The fiber could tightly adsorb the mutagens Trp-P-1, Trp-P-2, Glu-P-1 and A alpha C, and those generated in roasted coffee beans. The component that could destroy the mutagens was high-molecular-weight soluble polyphenolics. They might be converted into quinone derivatives in the presence of molecular oxygen. The quinone derivatives might destroy the mutagens. The fibers and the polyphenolics in one cup of brewed or instant coffee had the capacity to remove and destroy a substantial amount of the mutagens in pyrolysates of foodstuffs.
Mutagenicity of urine from individuals exposed to LPG combustion products.

PubMed

Yin, X J; Liu, J Z; Kong, X H; Chu, J H; Wang, H; Xiao, Z X

1998-09-01

The mutagenicity of urine from individuals exposed to the combustion products of liquefied petroleum gas (LPG) was detected with Salmonella typhimurium TA98 and its newly developed derivatives YG1021 (nitroreductase overproducing) and YG1024 (O-acetyltransferase overproducing). The detection showed significantly increased mutagenicity for the two YG strains and increased positive rates for all three strains in the presence of both rat liver S9 and beta-glucuronidase. Further analysis demonstrated that urine samples taken from smoking and non-smoking exposed individuals exhibited significantly higher mutagenic potency (revertants/10 microliters urine concentrate) than their corresponding controls. These results indicate that the increased urine mutagenicity is caused by the exposure to LPG combustion products or smoking. The mutagenic potency of urine samples of all exposed individuals tested with YG1024 was found to be about 7 times higher than with TA98. The difference in mutagenic potency was smaller for the same samples when comparison was made between YG1021 and TA98. This suggests that the mutagenic compounds present in the urine samples contain mainly aromatic compounds as glucuronide conjugates. Our results demonstrate that YG1024 is more sensitive than TA98 in detecting the mutagenicity of these samples. In addition, no significant difference in the mutagenic potency between the 'pure' exposed (non-smokers') and the 'pure' smokers' (unexposed) samples was found in all three tester strains. This might mean that the exposure extent of mutagens/carcinogens in LPG combustion products for exposed individuals roughly corresponds to the smoking level of smokers who smoke 20-40 cigarettes per day. Furthermore, the results also suggest that synergism might exist in the mutagenic effects of exposure to LPG combustion products and cigarette smoking.

URINARY MUTAGENICITY: A BIOMARKER OF GENOTOXIC EXPOSURES VIA AIR, WATER, AND DIET

EPA Science Inventory

During the past 30 years, ~100 studies have evaluated human urine for mutagenic activity using the Salmonella (Ames) mutagenicity assay. Urinary mutagenicity has been shown to correlate well with other biomarkers, including DNA and hemoglobin adducts, urinary metabolites, and chr...
Evidence for the presence of mutagenic arylamines in human breast milk and DNA adducts in exfoliated breast ductal epithelial cells.

PubMed

Thompson, Patricia A; DeMarini, David M; Kadlubar, Fred F; McClure, Gail Y; Brooks, Lance R; Green, Bridgett L; Fares, Manal Y; Stone, Angie; Josephy, P David; Ambrosone, Christine B

2002-01-01

Aromatic and heterocyclic amines are ubiquitous environmental mutagens present in combustion emissions, fried meats, and tobacco smoke, and are suspect human mammary carcinogens. To determine the presence of arylamines in breast tissue and fluid, we examined exfoliated breast ductal epithelial cells for DNA adducts and matched human milk samples for mutagenicity. Breast milk was obtained from 50 women who were 4-6 weeks postpartum, and exfoliated epithelial-cell DNA was evaluated for bulky, nonpolar DNA adducts by (32)P-postlabeling and thin-layer chromatography. Milk was processed by acid hydrolysis, and the extracted organics were examined in the standard plate-incorporation Ames Salmonella assay using primarily strain YG1024, which detects frameshift mutations and overexpresses aryl amine N-acetyltransferase. DNA adducts were identified in 66% of the specimens, and bulky adducts migrated in a pattern similar to that of 4-aminobiphenyl standards. The distribution of adducts did not vary by NAT2 genotype status. Of whole milk samples, 88% (22/25) had mutagenic activity. Among the samples for which we had both DNA adduct and mutagenicity data, 58% (14/19) of the samples with adducts were also mutagenic, and 85% (11/13) of the mutagenic samples had adducts. Quantitatively, no correlation was observed between the levels of adducts and the levels of mutagenicity. Separation of the milk showed that mutagenic activity was found in 69% of skimmed milk samples but in only 29% of the corresponding milk fat samples, suggesting that the breast milk mutagens were moderately polar molecules. Chemical fractionation showed that mutagenic activity was found in 67% (4/6) of the basic fractions but in only 33% (2/6) of acidic samples, indicating that the mutagens were primarily basic compounds, such as arylamines. Although pilot in nature, this study corroborates previous findings of significant levels of DNA adducts in breast tissue and mutagenicity in human breast milk and indicates that breast milk mutagens may be moderately polar basic compounds, such as arylamines.
Assessment of the mutagenic potential of ethanol auto engine exhaust gases by the Salmonella typhimurium microsomal mutagenesis assay, using a direct exposure method.

PubMed

Lotfi, C F; Brentani, M M; Böhm, G M

1990-08-01

The mutagenic activity of the new Brazilian fuel, ethanol, was determined by employing the Salmonella typhimurium microsomal mutagenesis assay (TA97, TA98, TA100, TA102, and TA104) and a direct exposure method. This methodology was first used to determine the mutagenic activity of gasoline, revealing mutagenic activity of base-pair substitution without any need for metabolic activation, indicating the presence of direct-action mutagens. Experiments with ethanol suggest an indirect mutagenic activity of the oxidant type. The exposure system was considered suitable for future studies of gaseous mixtures.
Mutagenicity of basic fractions derived from lamb and beef cooked by common household methods.

PubMed

Barrington, P J; Baker, R S; Truswell, A S; Bonin, A M; Ryan, A J; Paulin, A P

1990-03-01

Mutagen production was examined in lamb and beef in relation to certain common household cooking methods. Mutagenicity was assessed, after extraction of the basic fraction of cooked meat samples, using Salmonella typhimurium strain TA1538 with added rat-liver S-9 homogenate. Little or no mutagenicity was found in barbecued lamb chops, in microwave-cooked lamb chops, sirloin steak, leg of lamb, or rolled beef loaf, in roasted leg of lamb or rolled beef loaf, in stewed blade steak or in boiled chuck steak. However, the basic fraction from well-done, edible fried or grilled meat contained mutagenic activity equivalent to approximately 30,000 TA1538 revertants/100 g cooked meat. It was found tht the mutagenic activity of grilled lamb chops, sirloin and rump steaks was directly related to the average surface temperatures attained during cooking. Use of butter as a frying medium was particularly associated with higher mutagenicity in meat samples. Fried meats (rump and fillet steaks) generally yielded higher mutagenic activity than did grilled meats (rump steak, lamb chops) at comparable temperatures of the cooking medium. Using similar cooking procedures, lamb did not differ markedly from beef in mutagenic activity.
Mutagenic activity of overnight urine from healthy non-smoking subjects.

PubMed

Pavanello, Sofia; Lupi, Silvia; Pulliero, Alessandra; Gregorio, Pasquale; Saia, Bruno Onofrio; Clonfero, Erminio

2007-03-01

Urinary mutagenicity was evaluated in relation to environmental mutagen exposure (i.e., diet, indoor/outdoor activities, residential area etc.) on the day prior to sample collection, and also considering factors that contribute to the variability of Salmonella mutagenicity assay results. Overnight urine samples from 283 healthy non-smoking residents of northeast Italy (46% males, 20-62 years) were analyzed for mutagenicity on sensitive Salmonella typhimurium strain YG1024 with S9 mix employing the preincubation version of the plate incorporation assay (i.e., the Salmonella reverse mutation test). Urinary mutagenicity varied between 0.02 and 9.84 rev/ equiv. ml, and 7% of samples were positive (i.e., sample elicited a two-fold increase in revertants). There was an evident increase in mutagenicity in subjects with increased intake of mutagen-rich meals (n = 80) (P < 0.01 and positive urine 13% vs. 5%, P = 0.025). Indoor-exposed subjects (n = 65) also showed a higher percentage of positive urine (14% vs. 5%, P = 0.015). In particular, those subjects exposed to cooking fumes the previous evening (n = 28) revealed higher urinary mutagenicity (P = 0.035, positive urine 25% vs. 5%, P < 0.001) than non-indoor exposed. The sources of variability of the mutagenicity assay, mainly the histidine content of the urine concentrate (z = 4.06, P < 0.0001), and to a lesser extent bacterial inoculum size (z = 2.33, P = 0.019), also significantly influenced urinary mutagenicity values. In a linear multiple regression analysis, their effects were still significant (i.e., histidine content P = 0.026 and inoculum size P = 0.021), but the effects of diet, indoor exposure, and other environmental exposures (i.e., traffic and heating system exhausts, residential area) were not. It is concluded that the previous day's exposure to mutagen-rich meals and cooking fumes may influence the presence of mutagenic activity in the overnight urine of non-smoking subjects. This mutagenic activity, which remains in contact with bladder mucosa for several hours, could be considered risk factors for colorectal adenoma and possibly other cancers (i.e., bladder) in non-smokers. Accurate control of histidine content and bacterial inoculum size is strongly recommended when investigating the mutagenic activity of urine from non-smokers. (c) 2007 Wiley-Liss, Inc.
TOXICITY REDUCTION EVALUATION (TRE) AT A MUNICIPAL WASTEWATER TREATMENT PLANT USING MUTAGENICITY AS AN END- POINT

EPA Science Inventory

Previous work revealed substantial levels of mutagenicity in effluents from certain municipal wastewater treatment plants. One of these treatment plants was selected for further study to track the effluent mutagenicity to its sources, to chemically characterize the mutagenicity, ...
A level change in mutagenicity of Japanese tap water over the past 12 yr.

PubMed

Takanashi, Hirokazu; Kishida, Misako; Nakajima, Tsunenori; Ohki, Akira; Akiba, Michihiro

2011-05-01

A relative comparison study of mutagenicity in Japanese tap water was conducted for 1993 and 2005 surveys. It intended to assess the effects of advanced water treatment installations to water works, improvement of raw water quality and improvement of residual HOCl concentration controlling. Sampling points (taps) were the same in both surveys. The results of 245 samples obtained by the Ames Salmonella mutagenicity test (Ames test) were analyzed. The Ames tests were conducted by using Salmonella typhimurium TA98 and TA100 strains with and without exogenous activation (S9). With the exception of TA100-S9, the other conditions needed no discussion as a factor in the mutagenicity level change. The average mutagenicity in 1993 and 2005 under the conditions of TA100-S9 were 2600 and 1100 net revertantL(-1), respectively. This indicated that the mutagenicity level of Japanese tap water decreased during the 12-yr period. Particularly a remarkable decrease in mutagenicity was observed in the water works where the advanced water treatments were installed during the 12-yr period. The advanced water treatments were effective in decreasing the mutagenicity of tap water. Mutagenicity also decreased in the water works with conventional water treatments; the improvement of residual HOCl concentration controlling was also considered to be effective in decreasing the mutagenicity of tap water. Copyright © 2011 Elsevier Ltd. All rights reserved.
Discovering human germ cell mutagens with whole genome sequencing: Insights from power calculations reveal the importance of controlling for between-family variability.

PubMed

Webster, R J; Williams, A; Marchetti, F; Yauk, C L

2018-07-01

Mutations in germ cells pose potential genetic risks to offspring. However, de novo mutations are rare events that are spread across the genome and are difficult to detect. Thus, studies in this area have generally been under-powered, and no human germ cell mutagen has been identified. Whole Genome Sequencing (WGS) of human pedigrees has been proposed as an approach to overcome these technical and statistical challenges. WGS enables analysis of a much wider breadth of the genome than traditional approaches. Here, we performed power analyses to determine the feasibility of using WGS in human families to identify germ cell mutagens. Different statistical models were compared in the power analyses (ANOVA and multiple regression for one-child families, and mixed effect model sampling between two to four siblings per family). Assumptions were made based on parameters from the existing literature, such as the mutation-by-paternal age effect. We explored two scenarios: a constant effect due to an exposure that occurred in the past, and an accumulating effect where the exposure is continuing. Our analysis revealed the importance of modeling inter-family variability of the mutation-by-paternal age effect. Statistical power was improved by models accounting for the family-to-family variability. Our power analyses suggest that sufficient statistical power can be attained with 4-28 four-sibling families per treatment group, when the increase in mutations ranges from 40 to 10% respectively. Modeling family variability using mixed effect models provided a reduction in sample size compared to a multiple regression approach. Much larger sample sizes were required to detect an interaction effect between environmental exposures and paternal age. These findings inform study design and statistical modeling approaches to improve power and reduce sequencing costs for future studies in this area. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.
Genetic toxicology of thallium: a review.

PubMed

Rodríguez-Mercado, Juan José; Altamirano-Lozano, Mario Agustín

2013-07-01

This review summarizes the current knowledge about the general toxicity of thallium (Tl) and its environmental sources, with special emphasis placed on its potential mutagenic, genotoxic, and cytotoxic effects on both eukaryotic and prokaryotic cells. Tl is a nonessential heavy metal that poses environmental and occupational threats as well as therapeutic hazards because of its use in medicine. It is found in two oxidation states, thallous (Tl(+)) and thallic (Tl(3+)), both of which are considered highly toxic to human beings and domestic and wild organisms. Many Tl compounds are colorless, odorless and tasteless, and these characteristics, combined with the high toxicity of TI compounds, have led to their use as poisons. Because of its similarity to potassium ions (K(+)), plants and mammals readily absorb Tl(+) through the skin and digestive and respiratory systems. In mammals, it can cross the placental, hematoencephalic, and gonadal barriers. Inside cells, Tl can accumulate and interfere with the metabolism of potassium and other metal cations, mimicking or inhibiting their action. The effects of Tl on genetic material have not yet been thoroughly explored, and few existing studies have focused exclusively on Tl(+). Both in vivo and in vitro studies indicate that Tl compounds can have a weak mutagenic effect, but no definitive effect on the induction of primary DNA damage or chromosomal damage has been shown. These studies have demonstrated that Tl compounds are highly toxic and lead to changes in cell-cycle progression.
A direct method for nonlinear ill-posed problems

NASA Astrophysics Data System (ADS)

Lakhal, A.

2018-02-01

We propose a direct method for solving nonlinear ill-posed problems in Banach-spaces. The method is based on a stable inversion formula we explicitly compute by applying techniques for analytic functions. Furthermore, we investigate the convergence and stability of the method and prove that the derived noniterative algorithm is a regularization. The inversion formula provides a systematic sensitivity analysis. The approach is applicable to a wide range of nonlinear ill-posed problems. We test the algorithm on a nonlinear problem of travel-time inversion in seismic tomography. Numerical results illustrate the robustness and efficiency of the algorithm.
40 Years of the Salmonella Mutagenicity Assay: Implications for 21st Century Toxicology

EPA Science Inventory

The Salmonella (Ames) mutagenicity assay was developed and introduced by Bruce Ames and colleagues in 1971. Since then, it has become the standard assay for hazard identification of mutagens worldwide. It is a first-tier test for mutagenic activity in the pharmaceutical and chemi...
REVIEW OF THE SALMONELLA TYPHIMURIUM MUTAGENICITY OF BENZIDINE, BENZIDINE ANALOGUES, AND BENZIDINE-BASED DYES

EPA Science Inventory

The mutagenicity of benzidine analogues (including benzidine-based dyes) was reviewed with a primary emphasis on evaluating results of the Salmonella/microsome mutagenicity assay. Many of these amines are mutagenic in tester strains TA98 and TA100 but require exogenous mammalian ...
Examining the Preparatory Effects of Problem Generation and Solution Generation on Learning from Instruction

ERIC Educational Resources Information Center

Kapur, Manu

2018-01-01

The goal of this paper is to isolate the preparatory effects of problem-generation from solution generation in problem-posing contexts, and their underlying mechanisms on learning from instruction. Using a randomized-controlled design, students were assigned to one of two conditions: (a) problem-posing with solution generation, where they…
Examining Interactions between Problem Posing and Problem Solving with Prospective Primary Teachers: A Case of Using Fractions

ERIC Educational Resources Information Center

Xie, Jinxia; Masingila, Joanna O.

2017-01-01

Existing studies have quantitatively evidenced the relatedness between problem posing and problem solving, as well as the magnitude of this relationship. However, the nature and features of this relationship need further qualitative exploration. This paper focuses on exploring the interactions, i.e., mutual effects and supports, between problem…
Mutagenicity of fume particles from metal arc welding on stainless steel in the Salmonella/microsome test.

PubMed

Maxild, J; Andersen, M; Kiel, P

1978-01-01

Mutagenic activity of fume particles produced by metal arc welding on stainless steel (ss) is demonstrated by using the Salmonella/microsome mutagenicity test described by Ames et al., with strain TA100 (base-pair substitution) and TA98 (frame-shift reversion). Results of a representative but limited selection of processes and materials show that mutagenic activity is a function of process and process parameters. Welding on stainless steel produces particles that are mutagenic, whereas welding on mild steel (ms) produces particles that are not. Manual metal arc (MMA) welding on stainless steel produces particles of higher mutagenic activity than does metal inert gas (MIG) welding, and fume particles produced by MIG welding under short-arc transfer. Further studies of welding fumes (both particles and gases) must be performed to determine process parameters of significance for the mutagenic activity.
THE MUTAGENICITY OF METALLIZED AND UNMETALLIZED AZO AND FORMAZAN DYES IN THE SALMONELLA MUTAGENICITY ASSAY

EPA Science Inventory

The mutagenicity of metallized and unmetallized azo and formazan dyes in the Salmonella mutagenicity
Laura. C. Edwards', Harold S. Freeman'*, and Larry D. Claxton2

Abstract
In previous papers, the synthesis and chemical properties of iron complexed azo and formazan d...
ASSOCIATION BETWEEN URINARY MUTAGENICITY AND RISK OF COLORECTAL ADENOMAS IN A CLINIC-BASED CASE-CONTROL STUDY

EPA Science Inventory

ASSOCIATION BETWEEN URINARY MUTAGENICITY AND RISK OF COLORECTAL ADENOMAS IN A CLINIC-BASED CASE-CONTROL STUDY

Humans are exposed to a variety of mutagens from diet, smoking, or occupation. To explore if exposure to mutagens was related to the risk of colorectal adenomas i...
HAZARD IDENTIFICATION: EFFICIENCY OF SHORT-TERM TESTS IN IDENTIFYING GERM CELL MUTAGENS AND PUTATIVE NONGENOTOXIC CARCINOGENS

EPA Science Inventory

For more than a decade, mutagenicity tests have had a clearly defined role in the identification of potential human mutagens and an ancillary role in the identification of potential human carcinogens. he efficiency of short-term tests in identifying germ cell mutagens has been ex...
Fecalase: a model for activation of dietary glycosides to mutagens by intestinal flora

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tamura, G.; Gold, C.; Ferro-Luzzi, A.

1980-08-01

Many substances in the plant kingdom and in man's diet occur as glycosides. Recent studies have indicated that many glycosides that are not mutagenic in tests such as the Salmonella test become mutagenic upon hydrolysis of the glycosidic linkages. The Salmonella test utilizes a liver homogenate to approximate mammalian metabolism but does not provide a source of the enzymes present in intestinal bacterial flora that hydrolyze the wide variety of glycosides present in nature. We describe a stable cell-free extract of human feces, fecalase, which is shown to contain various glycosidases that allow the in vitro activation of many naturalmore » glycosides to mutagens in the Salmonella/liver homogenate test. Many beverages, such as red wine (but apparently not white wine) and tea, contain glycosides of the mutagen quercetin. Red wine, red grape juice, and teas were mutagenic in the test when fecalase was added, and red wine contained considerable direct mutagenic activity in the absence of fecalase. The implications of quercetin mutagenicity and carcinogenicity are discussed.« less
Effects of human placental S9 and induced rat liver S9 on the mutagenicity of drinking waters processed from humus-rich surface waters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vartiainen, T.; Lampelo, S.

The mutagenicity of chlorinated drinking waters processed from humus-rich surface waters has been shown to be very high. The effect of placental S9 on the mutagenicity of drinking waters has not been studied previously. The purpose of this study was to compare the effects of human placental and rat liver microsomal fractions on the mutagenicity of drinking waters processed from humus-rich surface waters. The samples of 34 drinking and two raw waters from 26 localities in Finland were tested for mutagenicity in Ames Salmonella typhimurium tester strain TA100 with and without metabolic activations. Between the drinking water samples, clear differencesmore » were recorded in the presence of placental and rat liver S9, suggesting different mutagens in the drinking waters. Rat liver S9 decreased the mutagenicities of drinking water concentrates, but placental S9 increased, decreased, or had no effect. It is not known if placental mutagenicity enhancing system might cause any health hazard to a developing fetus.« less

Phytoremediation of heavy metals--concepts and applications.

PubMed

Ali, Hazrat; Khan, Ezzat; Sajad, Muhammad Anwar

2013-05-01

The mobilization of heavy metals by man through extraction from ores and processing for different applications has led to the release of these elements into the environment. Since heavy metals are nonbiodegradable, they accumulate in the environment and subsequently contaminate the food chain. This contamination poses a risk to environmental and human health. Some heavy metals are carcinogenic, mutagenic, teratogenic and endocrine disruptors while others cause neurological and behavioral changes especially in children. Thus remediation of heavy metal pollution deserves due attention. Different physical and chemical methods used for this purpose suffer from serious limitations like high cost, intensive labor, alteration of soil properties and disturbance of soil native microflora. In contrast, phytoremediation is a better solution to the problem. Phytoremediation is the use of plants and associated soil microbes to reduce the concentrations or toxic effects of contaminants in the environments. It is a relatively recent technology and is perceived as cost-effective, efficient, novel, eco-friendly, and solar-driven technology with good public acceptance. Phytoremediation is an area of active current research. New efficient metal hyperaccumulators are being explored for applications in phytoremediation and phytomining. Molecular tools are being used to better understand the mechanisms of metal uptake, translocation, sequestration and tolerance in plants. This review article comprehensively discusses the background, concepts and future trends in phytoremediation of heavy metals. Copyright © 2013 Elsevier Ltd. All rights reserved.
Safety assessment of non-animal chondroitin sulfate sodium: Subchronic study in rats, genotoxicity tests and human bioavailability.

PubMed

Miraglia, Niccolò; Bianchi, Davide; Trentin, Antonella; Volpi, Nicola; Soni, Madhu G

2016-07-01

Chondroitin sulfate, an amino sugar polymer made of glucuronic acid and N-acetyl-galactosamine, is used in dietary supplements to promote joint health. Commonly used chondroitin sulfate is of animal origin and can pose potential safety problems including bovine spongiform encephalopathy (BSE). The objective of the present study was to investigate potential adverse effects, if any, of microbial derived chondroitin sulfate sodium (CSS) in subchronic toxicity, genotoxicity and bioavailability studies. In the toxicity study, Sprague Dawley rats (10/sex/group) were gavaged with CSS at dose levels of 0, 250, 500 and 1000 mg/kg body weight (bw)/day for 90-days. No mortality or significant changes in clinical signs, body weights, body weight gain or feed consumption were noted. Similarly, no toxicologically relevant treatment-related changes in hematological, clinical chemistry, urinalysis and organ weights were noted. Macroscopic and microscopic examinations did not reveal treatment-related abnormalities. In vitro mutagenic and clastogenic potentials as evaluated by Ames assay, chromosomal aberration test and micronucleus assay did not reveal genotoxicity of CSS. In pharmacokinetic study in human, CSS showed higher absorption as compared to chondroitin sulfate of animal origin. The results of subchronic toxicity study supports the no-observed-adverse-effect level (NOAEL) for CSS as 1000 mg/kg bw/day, the highest dose tested. Copyright © 2016 Elsevier Ltd. All rights reserved.
Improving attitudes toward mathematics learning with problem posing in class VIII

NASA Astrophysics Data System (ADS)

Vionita, Alfha; Purboningsih, Dyah

2017-08-01

This research is classroom action research which is collaborated to improve student's behavior toward math and mathematics learning at class VIII by using problem posing approach. The subject of research is all of students grade VIIIA which consist of 32 students. This research has been held on two period, first period is about 3 times meeting, and second period is about 4 times meeting. The instrument of this research is implementation of learning observation's guidance by using problem posing approach. Cycle test has been used to measure cognitive competence, and questionnaire to measure the students' behavior in mathematics learning process. The result of research shows the students' behavior has been improving after using problem posing approach. It is showed by the behavior's criteria of students that has increasing result from the average in first period to high in second period. Furthermore, the percentage of test result is also improve from 68,75% in first period to 78,13% in second period. On the other hand, the implementation of learning observation by using problem posing approach has also improving and it is showed by the average percentage of teacher's achievement in first period is 89,2% and student's achievement 85,8%. These results get increase in second period for both teacher and students' achievement which are 94,4% and 91,11%. As a result, students' behavior toward math learning process in class VIII has been improving by using problem posing approach.
[The toxicity variation of organic extracts in drinking water treatment processes].

PubMed

Mei, M; Wei, S; Zijian, W; Wenhua, W; Baohua, Z; Suxia, Z

2001-01-01

Source water samples and outlet water samples from different treatment processes of the Beijing Ninth Water Works were concentrated in situ with XAD-2 filled columns. GC-MS analysis and toxic assessment including acute toxicity evaluation by luminescent bacterium bioassay(Q67 strains) and mutagenicity assessment by Ames test(TA98 and TA100 strains with and without S9 addition) were conducted on these samples. The results showed that prechlorination caused the direct and indirect frame shift mutagenicity as well as indirect base pair substitute mutagenicity. Addition of coagulant may increase the base pair substitute mutagenic effects greatly. Sand and coal filtration and granular activated carbon filtration could effectively remove most of the formed mutagens. The rechlorination do not obviously increase the mutagenic effects. No mutagenic effect was observed in tap water. Acute toxicity showed the same variation with that of mutagenicity during the treatment processes. Sample from flocculation treatment process was found to be the most toxic sample. Results of GC-MS analysis showed that water in this plant was not contaminated by PCB. Concentrations of toluene, naphthalene and phenol increased in flocculation treatment process and in tap water. However, the concentrations of these substances were at the level of microgram/L, therefore, were not high enough to cause mutagenicity.
Mutagenicity of nitrogen compounds from synthetic crude oils: collection, separation and biological testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, T K; Epler, J L; Guerin, M R

1980-01-01

In order to determine the long range health effects such as carcinogenicity/mutagenicity/teratogenicity/toxicity, associated with the newly emerging energy technologies, we have utilized the Ames Salmonella assay to evaluate mutagenic properties of synthetic fuels. Coupling with class fractionation was necessary. Organic extraction and liquid/liquid partitioning was used to separate acidic and basic fraction. The neutral material was separated using Sephadex LH-20 gel filtration into saturated and aromatic fractions of various ring sizes. The alkaline fraction was subfractionated eluting with benzene and ethanol on a basic alumina column and then with isopropanol and acetone using a Sephadex LH-20 gel column. The frameshiftmore » strain TA-98 was utilized along with Aroclor-induced rat liver homogenate (S-9 mix) for the mutagenicity assay. The natural crude oils were slightly mutagenic, the polynucleararomatics constituting the activity, while the coal-derived fuels indicated mutagenicity associated with alkaline constituents as well as polyaromatics. Hydrotreated coal (H-coal, HDT) or Shale (Paraho-Shale oil, HDT) derived fuels were not mutagenic. Ninety percent of the mutagenic activity in alkaline fraction was recovered in the acetone subfraction. High resolution spectroscopy of this fraction indicates polycyclic aromatic primary amines along with azaarenes as organic constituents responsible for the mutagenic activity associated with shale- and coal-derived fuels.« less
Extending (Q)SARs to incorporate proprietary knowledge for regulatory purposes: A case study using aromatic amine mutagenicity.

PubMed

Ahlberg, Ernst; Amberg, Alexander; Beilke, Lisa D; Bower, David; Cross, Kevin P; Custer, Laura; Ford, Kevin A; Van Gompel, Jacky; Harvey, James; Honma, Masamitsu; Jolly, Robert; Joossens, Elisabeth; Kemper, Raymond A; Kenyon, Michelle; Kruhlak, Naomi; Kuhnke, Lara; Leavitt, Penny; Naven, Russell; Neilan, Claire; Quigley, Donald P; Shuey, Dana; Spirkl, Hans-Peter; Stavitskaya, Lidiya; Teasdale, Andrew; White, Angela; Wichard, Joerg; Zwickl, Craig; Myatt, Glenn J

2016-06-01

Statistical-based and expert rule-based models built using public domain mutagenicity knowledge and data are routinely used for computational (Q)SAR assessments of pharmaceutical impurities in line with the approach recommended in the ICH M7 guideline. Knowledge from proprietary corporate mutagenicity databases could be used to increase the predictive performance for selected chemical classes as well as expand the applicability domain of these (Q)SAR models. This paper outlines a mechanism for sharing knowledge without the release of proprietary data. Primary aromatic amine mutagenicity was selected as a case study because this chemical class is often encountered in pharmaceutical impurity analysis and mutagenicity of aromatic amines is currently difficult to predict. As part of this analysis, a series of aromatic amine substructures were defined and the number of mutagenic and non-mutagenic examples for each chemical substructure calculated across a series of public and proprietary mutagenicity databases. This information was pooled across all sources to identify structural classes that activate or deactivate aromatic amine mutagenicity. This structure activity knowledge, in combination with newly released primary aromatic amine data, was incorporated into Leadscope's expert rule-based and statistical-based (Q)SAR models where increased predictive performance was demonstrated. Copyright © 2016 Elsevier Inc. All rights reserved.
Halogenated 2,5-pyrrolidinediones: synthesis, bacterial mutagenicity in Ames tester strain TA-100 and semi-empirical molecular orbital calculations.

PubMed

Freeman, B A; Wilson, R E; Binder, R G; Haddon, W F

2001-02-20

The chloroimide 3,3-dichloro-4-(dichloromethylene)-2,5-pyrrolidinedione, a tetrachloroitaconimide, is the principal mutagen produced by chlorination of simulated poultry chiller water. It is the second most potent mutagenic disinfection by-product of chlorination ever reported. Six of seven new synthetic analogs of this compound are direct-acting mutagens in Ames tester strain TA-100. Computed energies of the lowest unoccupied molecular orbital (E(LUMO)) and of the radical anion stability (DeltaH(f)(rad)-DeltaH(f)) from MNDO-PM3 for the chloroimides show a quantitative correlation with the Ames TA-100 bacterial mutagenicity values. The molar mutagenicities of these direct acting mutagenic imides having an exocyclic double bond fit the same linear correlation (lnM(m) vs. E(LUMO); lnM(m) vs. DeltaH(f)(rad)--DeltaH(f)) as the chlorinated 2(5H)-furanones, including the potent mutagen MX, 3-chloro-4-(dichloro-methyl)-5-hydroxy-2(5H)-furanone, a by-product of water chlorination and paper bleaching with chlorine. Mutagenicity data for related haloimides having endocyclic double bonds are also given. For the same number of chlorine atoms, the imides with endocyclic double bonds have significantly higher Ames mutagenicity compared to their structural analogs with exocyclic double bonds, but do not follow the same E(LUMO) or DeltaH(f)(rad)-DeltaH(f) correlation as the exocyclic chloroimides and the chlorinated 2(5H)-furanones.
Mutagens from the cooking of food. II. Survey by Ames/Salmonella test of mutagen formation in the major protein-rich foods of the American diet.

PubMed

Bjeldanes, L F; Morris, M M; Felton, J S; Healy, S; Stuermer, D; Berry, P; Timourian, H; Hatch, F T

1982-08-01

The formation of mutagens in the major cooked protein-rich foods in the US diet was studied in the Ames Salmonella typhimurium test. The nine protein-rich foods most commonly eaten in the USA--ground beef, beef steak, eggs, pork chops, fried chicken, pot-roasted beef, ham, roast beef and bacon--were examined for their mutagenicity towards S. typhimurium TA1538 after normal 'household' cooking (deep frying, griddle/pan frying, baking/roasting, broiling, stewing, braising or boiling of 100-475 degrees C). Well-done fried ground beef, beef steak, ham pork chops and bacon showed significant mutagen formation. For chicken and beef steak high-temperature broiling produced the most mutagenicity, followed by baking/roasting and frying. Stewing, braising and deep frying produced little mutagen. Eggs and egg products produced mutagens only after cooking at high temperatures (the yolk to a greater extent than the white). Commercially cooked hamburgers showed a wide range of mutagenic activity. We conclude that mutagen formation following cooking of protein-containing foods is a complex function of food type, cooking time and cooking temperature. It seems clear that all the major protein-rich foods if cooked to a well-done state on the griddle (eggs only at temperatures above 225 degrees C) or by broiling will contain mutagens detectable by the Ames/Salmonella assay. This survey is a step towards determining whether any human health hazard results from cooking protein-rich foods. Further testing in both short- and long-term genotoxicity bioassays and carcinogenesis assays are needed before any human risk extrapolations can be made.
A well-posed optimal spectral element approximation for the Stokes problem

NASA Technical Reports Server (NTRS)

Maday, Y.; Patera, A. T.; Ronquist, E. M.

1987-01-01

A method is proposed for the spectral element simulation of incompressible flow. This method constitutes in a well-posed optimal approximation of the steady Stokes problem with no spurious modes in the pressure. The resulting method is analyzed, and numerical results are presented for a model problem.
Pose and Solve Varignon Converse Problems

ERIC Educational Resources Information Center

Contreras, José N.

2014-01-01

The activity of posing and solving problems can enrich learners' mathematical experiences because it fosters a spirit of inquisitiveness, cultivates their mathematical curiosity, and deepens their views of what it means to do mathematics. To achieve these goals, a mathematical problem needs to be at the appropriate level of difficulty,…
Applications: Students, the Mathematics Curriculum and Mathematics Textbooks

ERIC Educational Resources Information Center

Kilic, Cigdem

2013-01-01

Problem posing is one of the most important topics in a mathematics education. Through problem posing, students gain mathematical abilities and concepts and teachers can evaluate their students and arrange adequate learning environments. The aim of the present study is to investigate Turkish primary school teachers' opinions about problem posing…
Investigating the Impact of Field Trips on Teachers' Mathematical Problem Posing

ERIC Educational Resources Information Center

Courtney, Scott A.; Caniglia, Joanne; Singh, Rashmi

2014-01-01

This study examines the impact of field trip experiences on teachers' mathematical problem posing. Teachers from a large urban public school system in the Midwest participated in a professional development program that incorporated experiential learning with mathematical problem formulation experiences. During 2 weeks of summer 2011, 68 teachers…
Mutagen Synergy: Hypermutability Generated by Specific Pairs of Base Analogs

PubMed Central

Ang, Jocelyn; Song, Lisa Yun; D'Souza, Sara; Hong, Irene L.; Luhar, Rohan; Yung, Madeline

2016-01-01

ABSTRACT We tested pairwise combinations of classical base analog mutagens in Escherichia coli to study possible mutagen synergies. We examined the cytidine analogs zebularine (ZEB) and 5-azacytidine (5AZ), the adenine analog 2-aminopurine (2AP), and the uridine/thymidine analog 5-bromodeoxyuridine (5BrdU). We detected a striking synergy with the 2AP plus ZEB combination, resulting in hypermutability, a 35-fold increase in mutation frequency (to 53,000 × 10−8) in the rpoB gene over that with either mutagen alone. A weak synergy was also detected with 2AP plus 5AZ and with 5BrdU plus ZEB. The pairing of 2AP and 5BrdU resulted in suppression, lowering the mutation frequency of 5BrdU alone by 6.5-fold. Sequencing the mutations from the 2AP plus ZEB combination showed the predominance of two new hot spots for A·T→G·C transitions that are not well represented in either single mutagen spectrum, and one of which is not found even in the spectrum of a mismatch repair-deficient strain. The strong synergy between 2AP and ZEB could be explained by changes in the dinucleoside triphosphate (dNTP) pools. IMPORTANCE Although mutagens have been widely studied, the mutagenic effects of combinations of mutagens have not been fully researched. Here, we show that certain pairwise combinations of base analog mutagens display synergy or suppression. In particular, the combination of 2-aminopurine and zebularine, analogs of adenine and cytidine, respectively, shows a 35-fold increased mutation frequency compared with that of either mutagen alone. Understanding the mechanism of synergy can lead to increased understanding of mutagenic processes. As combinations of base analogs are used in certain chemotherapy regimens, including those involving ZEB and 5AZ, these results indicate that testing the mutagenicity of all drug combinations is prudent. PMID:27457718
Exposure related mutagens in urine of rubber workers associated with inhalable particulate and dermal exposure

PubMed Central

Vermeulen, R; Bos, R; Pertijs, J; Kromhout, H

2003-01-01

Aims: To determine the relation of the inhalation and dermal exposure routes and mutagenic activity in the urine of rubber workers (n = 105). Methods: Mutagenic activity of ambient total suspended particulate matter (TSPM), surface contamination wipes, and Sunday and weekday urine samples was assessed with S typhimurium YG1041 in the presence of a metabolic activation system. Each subject was grouped into one of two exposure categories for dermal exposure (high (≥25 revertants/cm2), low (<25 revertants/cm2)) based on the mutagenic activity detected on likely skin contact surfaces and into two airborne mutagenic exposure categories (high (≥210 revertants/m3), low (<210 revertants/m3)). The potential influence of skin aberrations and acetylation status (NAT2) on urinary mutagenicity levels was also evaluated. Results: A non-significant increase of +1605 revertants/g creatinine in urinary mutagenicity during the workweek relative to levels observed on Sunday was observed for the total population. Subsequent multivariate regression analyses, with the subjects' weekday urinary mutagenicity levels as the dependent variable, revealed associations with environmental and mainstream tobacco smoke exposure, with the level of mutagenic contamination on surfaces with which the subjects had likely contact, with the subjects' inhalable particulate exposure level, with observed mild skin aberrations, and when the subjects had a slow acetylation phenotype. Similar associations, although weaker were observed with Sunday urinary mutagenicity levels as well, except for the association with slow acetylation phenotype. Based on measured exposure levels it could be estimated that a high potential for exposure to surface contamination with mutagenic activity increased weekday urinary mutagenicity by about 62% when compared to low exposed workers, while high inhalable particulate exposure levels increased weekday urinary mutagenicity levels by about 21%. Subjects with mild skin aberrations had an additional, non-significant, increase in weekday urinary mutagenic activity compared to subjects without any skin aberrations. Discussion: Results suggest that the dermal exposure route may contribute more to the level of genotoxic compounds in urine of rubber workers than the inhalation route. Although the study was limited in size, the results warrant further investigation in the importance of and ways to effectively control the dermal exposure route in the rubber industry. PMID:12554836
Cultural and Political Vignettes in the English Classroom: Problem-Posing, Problem-Solving, and the Imagination

ERIC Educational Resources Information Center

Darvin, Jacqueline

2009-01-01

One way to merge imagination with problem-posing and problem-solving in the English classroom is by asking students to respond to "cultural and political vignettes" (CPVs). CPVs are cultural and political situations that are presented to students so that they can practice the creative and essential decision-making skills that they will need to use…
High-School Students' Approaches to Solving Algebra Problems that Are Posed Symbolically: Results from an Interview Study

ERIC Educational Resources Information Center

Huntley, Mary Ann; Davis, Jon D.

2008-01-01

A cross-curricular structured-probe task-based clinical interview study with 44 pairs of third year high-school mathematics students, most of whom were high achieving, was conducted to investigate their approaches to a variety of algebra problems. This paper presents results from three problems that were posed in symbolic form. Two problems are…
A comparison of mutagen production in fried ground chicken and beef: effect of supplemental creatine.

PubMed

Knize, M G; Shen, N H; Felton, J S

1988-11-01

Ground chicken breast and ground beef with either endogenous or a 10-fold increase in the concentration of creatine were fried at 220 degrees C for 10 min per side. One patty (100 g) of chicken meat yielded 120,000 Salmonella (TA1538) revertants following metabolic activation. The pan residues had 39% of the total activity. Added creatine (10-fold the endogenous level) increased mutagen yields an average of 2-fold. Beef cooked under identical conditions yielded 150,000 revertants/100 g for the meat patties and pan residues combined. Added creatine to beef prior to cooking increased mutagen yields 3-fold. The mutagenic profiles following initial HPLC separation showed that chicken samples with endogenous or added creatine were remarkably similar. Chicken and beef HPLC mutagenicity profiles were also similar to each other, but not identical. This suggests that the general mutagen-forming reactions with the two different types of muscle are qualitatively similar with only minor quantitative differences. The pan residues from both meat types with and without added creatine showed some significant differences in the mutagen peak profile. This work suggests that the types of mutagens formed in chicken are similar to those formed in beef and that creatine appears to be involved in the formation of all the mutagenic compounds produced from fried muscle tissue.
Detection of ultra-low levels of DNA changes by drinking water: epidemiologically important finding.

PubMed

Kumari, Parmila; Kamiseki, Meiko; Biyani, Manish; Suzuki, Miho; Nemoto, Naoto; Aita, Takuyo; Nishigaki, Koichi

2015-02-01

The safety of drinking water is essential to our health. In this context, the mutagenicity of water needs to be checked strictly. However, from the methodological limit, the lower concentration (less than parts per million) of mutagenicity could not be detected, though there have been of interest in the effect of less concentration mutagens. Here, we describe a highly sensitive mutation assay that detects mutagens at the ppb level, termed genome profiling-based mutation assay (GPMA). This consists of two steps; (i) Escherichia coli culture in the medium with/without mutagens and (ii) Genome profiling (GP) method (an integrated method of random PCR, temperature gradient gel electrophoresis and computer-aided normalization). Owing to high sensitivity of this method, very low concentration of mutagens in tap water could be directly detected without introducing burdensome concentration processes, enabling rapid measurement of low concentration samples. Less expectedly, all of the tap waters tested (22 samples) were shown to be significantly mutagenic while mineral waters were not. Resultantly, this article informs two facts that the GPMA method is competent to measure the mutagenicity of waters directly and the experimental results supported the former reports that the city tap waters contain very low level of mutagenicity reagent trihalomethanes. © The Authors 2014. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.
A reaction mechanism-based prediction of mutagenicity: α-halo carbonyl compounds adduct with DNA by SN2 reaction.

PubMed

Haranosono, Yu; Ueoka, Hiroki; Kito, Gakushi; Nemoto, Shingo; Kurata, Masaaki; Sakaki, Hideyuki

2018-01-01

Most of the α-halo carbonyl (AHC) compounds tend to be predicted as mutagenic by structure-activity relationship based on structural category only, because they have an alkyl halide structure as a structural alert of mutagenicity. However, some AHC compounds are not mutagenic. We hypothesized that AHC reacts with DNA by S N 2 reaction, and the reactivity relates to mutagenicity. As an index of S N 2 reactivity, we focused on molecular orbitals (MOs), as the direction and position of two molecules in collision are important in the S N 2 reaction. The MOs suitable for S N 2 reaction (SN2MOs) were selected by chemical-visual inspection based on the shape of the MO. We used the level gap and the energy gap between SN2MO and the lowest unoccupied molecular orbital as the descriptors of S N 2 reactivity. As the results, S N 2 reactivity related to mutagenicity and we were able to predict mutagenicity of 20 AHC compounds with 95.0% concordance. It was suggested that S N 2 reaction is a reaction mechanism of AHC compounds and DNA in the mutagenic process. The method allows for discrimination among structurally similar compounds by combination with quantitative structure-activity relationships. The combination approach is expected to be useful for the mutagenic assessment of pharmaceutical impurities.
A truncated generalized singular value decomposition algorithm for moving force identification with ill-posed problems

NASA Astrophysics Data System (ADS)

Chen, Zhen; Chan, Tommy H. T.

2017-08-01

This paper proposes a new methodology for moving force identification (MFI) from the responses of bridge deck. Based on the existing time domain method (TDM), the MFI problem eventually becomes solving the linear algebraic equation in the form Ax = b . The vector b is usually contaminated by an unknown error e generating from measurement error, which often called the vector e as ''noise''. With the ill-posed problems that exist in the inverse problem, the identification force would be sensitive to the noise e . The proposed truncated generalized singular value decomposition method (TGSVD) aims at obtaining an acceptable solution and making the noise to be less sensitive to perturbations with the ill-posed problems. The illustrated results show that the TGSVD has many advantages such as higher precision, better adaptability and noise immunity compared with TDM. In addition, choosing a proper regularization matrix L and a truncation parameter k are very useful to improve the identification accuracy and to solve ill-posed problems when it is used to identify the moving force on bridge.

Review: putative mutagens and carcinogens in foods. VII. Genetic toxicology of the diet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatch, F.T.; MacGregor, J.T.; Zeiger, E.

Individual reviews of approximately 30 papers presented at the Fourth International Conference on Environmental Mutagens are presented in this report. Topics covered include diet in cancer epidemiology; cooked and processed food as a source of mutagens and carcinogens; natural genotoxins in plants and beverages; mutagens within the gastrointestinal tract; and modulation of mutagenesis and carcinogenesis.
The Concentrations but Not the Components of Particulate Material and Secondary Transformation Products May Account for Much of the Variation in Air Mutagenicity

EPA Science Inventory

The mutagenic potency of ambient air PM in the Salmonella mutagenicity assay (rev/mg PM) varies only ~1 order of magnitude worldwide; however, the mutagenic potency of the air itself (rev/m3 of air) varies ~5 orders of magnitude (IARC Monograph Vol 109, 2016). Thus, the componen...
Mutagenicity of diesel exhaust particle extracts: influence of fuel composition in two diesel engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, C.R.; Henderson, T.R.; Royer, R.E.

The influence of diesel fuel composition on mutagenicity of exhaust particle associated organic compounds has been investigated using nine fuels varying in aromatic content and distillation properties. The tests were conducted with Oldsmobile Delta-88 and Peugot 504 diesel cars operated according to the EPA Federal Test Procedure. The particulate exhaust from each test was collected on a filter, extracted in dichloromethane and the resulting extract evaluated for mutagenicity in Salmonella strain TA-100. Mutagenicity of extracts of particles collected from the Oldsmobile were highest in the higher aromatic content fuels (greater than 30%) but similar for intermediate (20%) and low (13%)more » aromatic content fuels. No influence of aromaticity on mutagenicity was observed in samples collected from the Peugeot under the same conditions. Thus, fuel aromatic content may enhance the production of mutagenic combustion products at higher concentrations, but may be dependent upon engine type. A good correlation was observed between mutagenicity of the particle extracts and the initial boiling point of the fuel (r . 0.89). Gas chromatography/mass spectrometric analysis of the aromatic fraction of the fuels showed that the fuel producing the most mutagenic combustion products was highest in phenanthrene type compounds.« less
Mutagenicity of diesel exhaust particle extracts: influence of fuel composition in two diesel engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, C.R.; Henderson, T.R.; Royer, R.E.

The influence of diesel fuel composition on mutagenicity of exhaust particle associated organic compounds has been investigated using nine fuels varying in aromatic content and distillation properties. The tests were conducted with Oldsmobile Delta-88 and Peugot 504 diesel cars operated according to the EPA Federal Test Procedure. The particulate exhaust from each test was collected on a filter, extracted in dichloromethane and the resulting extract evaluated for mutagenicity in Salmonella strain TA-100. Mutagenicity of extracts of particles collected from the Oldsmobile were highest in the higher aromatic content fuels (> 30%) but similar for intermediate (20%) and low (13%) aromaticmore » content fuels. No influence of aromaticity on mutagenicity was observed in samples collected from the Peugeot under the same conditions. Thus, fuel aromatic content may enhance the production of mutagenic combustion products at higher concentrations, but may be dependent upon engine type. A good correlation was observed between mutagenicity of the particle extracts and the initial boiling point of the fuel (r = 0.89). Gas chromatography/mass spectrometric analysis of the aromatic fraction of the fuels showed that the fuel producing the most mutagenic combustion products was highest in phenanthrene type compounds.« less
QSAR modeling for predicting mutagenic toxicity of diverse chemicals for regulatory purposes.

PubMed

Basant, Nikita; Gupta, Shikha

2017-06-01

The safety assessment process of chemicals requires information on their mutagenic potential. The experimental determination of mutagenicity of a large number of chemicals is tedious and time and cost intensive, thus compelling for alternative methods. We have established local and global QSAR models for discriminating low and high mutagenic compounds and predicting their mutagenic activity in a quantitative manner in Salmonella typhimurium (TA) bacterial strains (TA98 and TA100). The decision treeboost (DTB)-based classification QSAR models discriminated among two categories with accuracies of >96% and the regression QSAR models precisely predicted the mutagenic activity of diverse chemicals yielding high correlations (R 2 ) between the experimental and model-predicted values in the respective training (>0.96) and test (>0.94) sets. The test set root mean squared error (RMSE) and mean absolute error (MAE) values emphasized the usefulness of the developed models for predicting new compounds. Relevant structural features of diverse chemicals that were responsible and influence the mutagenic activity were identified. The applicability domains of the developed models were defined. The developed models can be used as tools for screening new chemicals for their mutagenicity assessment for regulatory purpose.
Genotoxicity of processed food items and ready-to-eat snacks in Finland.

PubMed

Omoruyi, Iyekhoetin Matthew; Pohjanvirta, Raimo

2014-11-01

Processed foods are an insufficiently characterized source of chemical mutagens for consumers. Here, we evaluated the genotoxicity of selected food products in Finland. Mutagenicity was determined by the standard plate incorporation assay followed by methylcellulose overlay and treat-and-wash assays, using the Salmonella strains TA 100 and 98 with and without metabolic activation. Generally, the mutagenic activity of food samples was low, but exhibited lot-wise variation. Cold cuts of cold-smoked beef, grilled turkey, and smoked chicken (a single batch of each) were mutagenic in all three assays with the TA 100 strain with and without metabolic activation, indicating the mutagenic effect was not secondary to histidine release from the food products. However, none of the food extracts showing mutagenic potential induced DNA damage in vitro using the Comet Assay. Our findings imply that in Finland today, there are still products the production methods of which should be refined to reduce the potential risk of mutagenicity to consumers. Copyright © 2014 Elsevier Ltd. All rights reserved.
Mutagenic activity of austocystins - secondary metabolites of Aspergillus ustus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kfir, R.; Johannsen, E.; Vleggaar, R.

1986-11-01

Mycotoxins constitute a group of toxic secondary fungal metabolites. Fungi that produce these toxins frequently contaminate food and feed, creating a potential threat to human and animal health. Biological activities of mycotoxins include, amongst others: toxicity, mutagenicity and carcinogenicity, which can be expressed with or without metabolic activation. Austocystins are similar in structure to aflatoxin B/sup 1/ and are probably synthesized in a similar manner. The Ames Salmonella test, a widely accepted method employed for the detection of mutagenic activity of various chemical compounds was used for testing the mutagenic activity of different mycotoxins. As aflatoxin B/sup 1/ was foundmore » by the Ames test to be highly mutagenic, the same test was applied for the study of possible mutagenicity of the austocystins. The mutagenic activity of these compounds was studied with and without metabolic activation using two tester strains of S. typhimurium, one capable of detecting frame shift mutation (strain TA98) and the other capable of detecting base pair substitution (strain TA100).« less
Role of ozone and granular activated carbon in the removal of mutagenic compounds.

PubMed Central

Bourbigot, M M; Hascoet, M C; Levi, Y; Erb, F; Pommery, N

1986-01-01

The identification of certain organic compounds in drinking water has led water treatment specialists to be increasingly concerned about the eventual risks of such pollutants to the health of consumers. Our experiments focused on the role of ozone and granular activated carbon in removing mutagenic compounds and precursors that become toxic after chlorination. We found that if a sufficient dose of ozone is applied, its use does not lead to the creation of mutagenic compounds in drinking water and can even eliminate the initial mutagenicity of the water. The formation of new mutagenic compounds seems to be induced by ozonation that is too weak, although these mutagens can be removed by GAC filtration. Ozone used with activated carbon can be one of the best means for eliminating the compounds contributing to the mutagenicity of water. A combined treatment of ozone and activated carbon also decreases the chlorine consumption of the treated water and consequently reduces the formation of chlorinated organic compounds. PMID:3816720
Tecnología Digital y Formulación de Problemas durante el Proceso de Resolución de Problemas = Digital Technology and Formulation of Problems during the Process of Solving Problems

ERIC Educational Resources Information Center

Aguilar-Magallón, Daniel Aurelio; Reyes-Martìnez, Isaid

2016-01-01

We analyze and discuss ways in which prospective high school teachers pose and pursue questions or problems during the process of reconstructing dynamic configurations of figures given in problem statements. To what extent does the systematic use of a Dynamic Geometry System (DGS) help the participants engage in problem posing activities…
Mutagens and carcinogens - Occurrence and role during chemical and biological evolution

NASA Technical Reports Server (NTRS)

Giner-Sorolla, A.; Oro, J.

1981-01-01

The roles of mutagenic and carcinogenic substances in early biologic evolution is examined, along with terrestrial and extraterrestrial sources of mutagens and carcinogens. UV solar radiation is noted to have served to stimulate prebiotic life while also causing harmful effects in plants and animals. Aromatic compounds have been found in meteorites, and comprise leukemogens, polycyclic hydrocarbons, and nitrasamine precursors. Other mutagenic sources are volcanoes, and the beginning of evolution with mutagenic substances is complicated by the appearance of malignancies due to the presence of carcinogens. The atmosphere of the Precambrian period contained both mutagens and early carcinogens and, combined with volcanic activity discharges, formed an atmospheric chemical background analogous to the background ionizing radiation. Carcinogenesis is concluded to be intrinsic to nature, having initiated evolution and, eventually, cancer cells.
Mutagenic activation reduces carcinogenic activity of ortho-aminoazotoluene for mouse liver.

PubMed

Ovchinnikova, L P; Bogdanova, L A; Kaledin, V I

2013-03-01

Pentachlorophenol (aromatic amine and azo stain metabolic stimulation inhibitor) reduced the hepatocarcinogenic activity of 4-aminoazobenzene and reduced that of ortho-aminoazotoluene in suckling mice. Both 4-aminoazobenzene and ortho-aminoazotoluene exhibited mutagenic activity in Ames' test in vitro on S. typhimurium TA 98 strain with activation with liver enzymes; this mutagenic activity was similarly suppressed by adding pentachlorophenol into activation medium. Induction of xenobiotic metabolism enzymes, stimulating the mutagenic activity of ortho-aminoazotoluene, suppressed its carcinogenic effect on mouse liver. Hence, ortho-aminotoluene (the initial compound), but not its mutagenic metabolites, was the direct active hepatocarcinogen for mice.
Occurrence of mutagens in canned foods.

PubMed

Krone, C A; Iwaoka, W T

1984-01-01

Mutagens are shown to be present in a variety of commercially heat-processed foods. Since these substances are not present in the unheated raw material, it appears that they are produced during processing. Canned salmon and beef broth showed the highest mutagenicity while other canned beef and fish products yielded lower but detectable levels. These findings are significant not only because of the large proportion of the food supply which is processed by canning, but also because the mutagens in these foods exhibit chemical behaviors and Salmonella strain specificity similar to mutagens in grilled foods which have been shown to be mammalian carcinogens.
Potential of plant genetic systems for monitoring and screening mutagens

PubMed Central

Nilan, R. A.

1978-01-01

Plants have too long been ignored as useful screening and monitoring systems of environmental mutagens. However, there are about a dozen reliable, some even unique, plant genetic systems that can increase the scope and effectiveness of chemical and physical mutagen screening and monitoring procedures. Some of these should be included in the Tier II tests. Moreover, plants are the only systems now in use as monitors of genetic effects caused by polluted atmosphere and water and by pesticides. There are several major advantages of the plant test systems which relate to their reproductive nature, easy culture and growth habits that should be considered in mutagen screening and monitoring. In addition to these advantages, the major plant test systems exhibit numerous genetic and chromosome changes for determining the effects of mutagens. Some of these have not yet been detected in other nonmammalian and mammalian test systems, but probably occur in the human organism. Plants have played major roles in various aspects of mutagenesis research, primarily in mutagen screening (detection and verification of mutagenic activity), mutagen monitoring, and determining mutagen effects and mechanisms of mutagen action. They have played lesser roles in quantification of mutagenic activity and understanding the nature of induced mutations. Mutagen monitoring with plants, especially in situ on land or in water, will help determine potential genetic hazards of air and water pollutants and protect the genetic purity of crop plants and the purity of the food supply. The Tradescantia stamen-hair system is used in a mobile laboratory for determining the genetic effects of industrial and automobile pollution in a number of sites in the U.S.A. The fern is employed for monitoring genetic effects of water pollution in the Eastern states. The maize pollen system and certain weeds have monitored genetic effects of pesticides. Several other systems that have considerable value and should be developed and more widely used in mutagen monitoring and screening, especially for in situ monitoring, are discussed. Emphasis is placed on pollen systems in which changes in pollen structure, chemistry, and chromosomes can be scored for monitoring; and screening systems which can record low levels of genetic effects as well as provide information on the nature of induced mutations. The value of plant systems for monitoring and screening mutagens can be improved by: greater knowledge of plant cell processes at the molecular and ultrastructural levels; relating these processes to mutagen effects and plant cell responses; improving current systems for increased sensitivity, ease of detecting genetic and chromosome changes, recording of data (including automation), and for extending the range of genetic and chromosome end points; and designing and developing new systems with the aid of previous and current botanical and genetic knowledge. PMID:367768
Mutagenicity in drug development: interpretation and significance of test results.

PubMed

Clive, D

1985-03-01

The use of mutagenicity data has been proposed and widely accepted as a relatively fast and inexpensive means of predicting long-term risk to man (i.e., cancer in somatic cells, heritable mutations in germ cells). This view is based on the universal nature of the genetic material, the somatic mutation model of carcinogenesis, and a number of studies showing correlations between mutagenicity and carcinogenicity. An uncritical acceptance of this approach by some regulatory and industrial concerns is over-conservative, naive, and scientifically unjustifiable on a number of grounds: Human cancers are largely life-style related (e.g., cigarettes, diet, tanning). Mutagens (both natural and man-made) are far more prevalent in the environment than was originally assumed (e.g., the natural bases and nucleosides, protein pyrolysates, fluorescent lights, typewriter ribbon, red wine, diesel fuel exhausts, viruses, our own leukocytes). "False-positive" (relative to carcinogenicity) and "false-negative" mutagenicity results occur, often with rational explanations (e.g., high threshold, inappropriate metabolism, inadequate genetic endpoint), and thereby confound any straightforward interpretation of mutagenicity test results. Test battery composition affects both the proper identification of mutagens and, in many instances, the ability to make preliminary risk assessments. In vitro mutagenicity assays ignore whole animal protective mechanisms, may provide unphysiological metabolism, and may be either too sensitive (e.g., testing at orders-of-magnitude higher doses than can be ingested) or not sensitive enough (e.g., short-term treatments inadequately model chronic exposure in bioassay). Bacterial systems, particularly the Ames assay, cannot in principle detect chromosomal events which are involved in both carcinogenesis and germ line mutations in man. Some compounds induce only chromosomal events and little or no detectable single-gene events (e.g., acyclovir, caffeine, methapyrilene). In vivo mutagenicity assays are more physiological but appear to be relatively insensitive due to the inability to achieve sufficiently high acute plasma levels to mimic cumulative long-term effects. Examination of the mutagenicity of naturally occurring analogs may indicate the irrelevance of a test compound's mutagenicity (e.g., deoxyguanosine and the structurally related antiviral drug, acyclovir, have identical mutagenicity patterns). Life-threatening or severe debilitating diseases (e.g., cancer, severe psychoses, severe crippling arthritis, sight-threatening diseases) may justify treatment with mutagenic or even carcinogenic therapeutic agents (benefit/risk considerations).(ABSTRACT TRUNCATED AT 400 WORDS)
EVALUATION OF NEW 2,2-DIMETHYL-5,5-DIPROPOXYBENZIDINE- AND 3,3-DIPROPOXYBENZIDINE-BASED DIRECT DYE ANALOGS FOR MUTAGENIC ACTIVITY BY USE OF THE SALMONELLA/MAMMALIAN MUTAGENICITY ASSAY

EPA Science Inventory

A series of new metallized and unmetallized direct dyes based on benzidine analogs, 2,2'dimethyl-5,5'-dipropoxybenzidine and 3,3'-dipropoxybenzidine, were evaluated for mutagenicity in Salmonella typhimurium strains TA98 and TA100. All of the dyes examined were judged non-mutagen...
Solving ill-posed control problems by stabilized finite element methods: an alternative to Tikhonov regularization

NASA Astrophysics Data System (ADS)

Burman, Erik; Hansbo, Peter; Larson, Mats G.

2018-03-01

Tikhonov regularization is one of the most commonly used methods for the regularization of ill-posed problems. In the setting of finite element solutions of elliptic partial differential control problems, Tikhonov regularization amounts to adding suitably weighted least squares terms of the control variable, or derivatives thereof, to the Lagrangian determining the optimality system. In this note we show that the stabilization methods for discretely ill-posed problems developed in the setting of convection-dominated convection-diffusion problems, can be highly suitable for stabilizing optimal control problems, and that Tikhonov regularization will lead to less accurate discrete solutions. We consider some inverse problems for Poisson’s equation as an illustration and derive new error estimates both for the reconstruction of the solution from the measured data and reconstruction of the source term from the measured data. These estimates include both the effect of the discretization error and error in the measurements.
Toxicological and chemical characterization of the process stream materials and gas combustion products of an experimental low-btu coal gasifier.

PubMed

Benson, J M; Hanson, R L; Royer, R E; Clark, C R; Henderson, R F

1984-04-01

The process gas stream of an experimental pressurized McDowell-Wellman stirred-bed low-Btu coal gasifier, and combustion products of the clean gas were characterized as to their mutagenic properties and chemical composition. Samples of aerosol droplets condensed from the gas were obtained at selected positions along the process stream using a condenser train. Mutagenicity was assessed using the Ames Salmonella mammalian microsome mutagenicity assay (TA98, with and without rat liver S9). All materials required metabolic activation to be mutagenic. Droplets condensed from gas had a specific mutagenicity of 6.7 revertants/microgram (50,000 revertants/liter of raw gas). Methylnaphthalene, phenanthrene, chrysene, and nitrogen-containing compounds were positively identified in a highly mutagenic fraction of raw gas condensate. While gas cleanup by the humidifier-tar trap system and Venturi scrubber led to only a small reduction in specific mutagenicity of the cooled process stream material (4.1 revertants/microgram), a significant overall reduction in mutagenicity was achieved (to 2200 revertants/liter) due to a substantial reduction in the concentration of material in the gas. By the end of gas cleanup, gas condensates had no detectable mutagenic activity. Condensates of combustion product gas, which contained several polycyclic aromatic compounds, had a specific mutagenicity of 1.1 revertants/microgram (4.0 revertants/liter). Results indicate that the process stream material is potentially toxic and that care should be taken to limit exposure of workers to the condensed tars during gasifier maintenance and repair and to the aerosolized tars emitted in fugitive emissions. Health risks to the general population resulting from exposure to gas combustion products are expected to be minimal.
Emission of polycyclic aromatic hydrocarbons, toxicity, and mutagenicity from domestic cooking using sawdust briquettes, wood, and kerosene.

PubMed

Kim, OanhNguyenThi; Nghiem, Le Hoang; Phyu, Yin Latt

2002-03-01

Smoke samples, in both gas and particulate matter (PM) phases, of the three domestic stoves were collected using U.S. EPA modified method 5 and were analyzed for 17 PAH (HPLC-UV), acute toxicity (Microtox test), and mutagenicity (Amestest). The gas phase of smoke contributed > or = 95% of 17 PAH, > or = 96% of toxicity, and > or = 60% of mutagenicity. The highest emission factor of 17 PAH was from sawdust briquettes (260 mg/kg), but the highest emission of 11 genotoxic PAH was from kerosene (28 mg/kg). PM samples of kerosene smoke were not toxic. The total toxicity emission factor was the highest from sawdust, followed by kerosene and wood fuel. Smoke samples from the kerosene stove were not mutagenic. TA98 indicated the presence of both direct and indirect mutagenic activities in PM samples of sawdust and wood fuel but only direct mutagenic activities in the gas phase. TA100 detected only direct mutagenic activities in both PM and gas-phase samples. The higher mutagenicity emission factor was from wood fuel, 12 x 10(6) revertants/kg (TA100-S9) and 3.5 x 10(6) (TA98-S9), and lower from sawdust, 2.9 x 10(6) (TA100-S9) and 2.8 x 10(6) (TA98-S9). The low burning rate and high efficiency of a kerosene stove have resulted in the lowest PAH, toxicity, and mutagenicity emissions from daily cooking activities. The bioassays produced toxicity and mutagenicity results in correspondence with the PAH content of samples. The tests could be used for a quick assessment of potential health risks.
Survey of the mutagenicity of surface water, sediments, and drinking water from the Penobscot Indian Nation.

PubMed

Warren, Sarah H; Claxton, Larry D; Diliberto, Janet; Hughes, Thomas J; Swank, Adam; Kusnierz, Daniel H; Marshall, Valerie; DeMarini, David M

2015-02-01

U.S. Environmental Protection Agency (US EPA) Regional Applied Research Effort (RARE) projects address the effects of environmental pollutants in a particular region on the health of the population in that region. This report is part of a RARE project that addresses this for the Penobscot Indian Nation (PIN), Penobscot Island, Maine, U.S., where the Penobscot River has had fish advisories for many years due to high levels of mercury. We used the Salmonella mutagenicity assay with strains TA100, TA98, YG1041, and YG1042 with and without metabolic activation to assess the mutagenic potencies of organic extracts of the Penobscot River water and sediment, as well as drinking-water samples, all collected by the PIN Department of Natural Resources. The source water for the PIN drinking water is gravel-packed groundwater wells adjacent to the Penobscot River. Most samples of all extracts were either not mutagenic or had low to moderate mutagenic potencies. The average mutagenic potencies (revertants/L-equivalent) were 337 for the drinking-water extracts and 177 for the river-water extracts; the average mutagenic potency for the river-sediment extracts was 244 revertants(g-equivalent)(-1). This part of the RARE project showed that extracts of the Penobscot River water and sediments and Penobscot drinking water have little to no mutagenic activity that might be due to the classes of compounds that the Salmonella mutagenicity assay detects, such as polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (nitroarenes), and aromatic amines. This study is the first to examine the mutagenicity of environmental samples from a tribal nation in the U.S. Published by Elsevier Ltd.
Bacterial and human cell mutagenicity study of some C18H10 cyclopenta-fused polycyclic aromatic hydrocarbons associated with fossil fuels combustion.

PubMed Central

Lafleur, A L; Longwell, J P; Marr, J A; Monchamp, P A; Plummer, E F; Thilly, W G; Mulder, P P; Boere, B B; Cornelisse, J; Lugtenburg, J

1993-01-01

A number of isomeric C18H10 polycyclic aromatic hydrocarbons (PAHs), thought to be primarily cyclopenta-fused PAHs, are produced during the combustion and pyrolysis of fossil fuels. To determine the importance of their contributions to the total mutagenic activity of combustion and pyrolysis samples in which they are found, we characterized reference quantities of four C18H10 CP-PAHs: benzo[ghi]fluoranthene (BF), cyclopenta[cd]pyrene (CPP), cyclopent[hi]acephenanthrylene (CPAP), and cyclopent[hi]aceanthrylene (CPAA). Synthesis of CPAA and CPAP is described. The availability of reference samples of these isomers also proved to be an essential aid in the identification of the C18H10 species often found in combustion and pyrolysis samples. Chemical analysis of selected combustion and pyrolysis samples showed that CPP was generally the most abundant C18H10 isomer, followed by CPAP and BF. CPAA was detected only in pyrolysis products from pure PAHs. We tested the four C18H10 PAHs for mutagenicity in a forward mutation assay using S. typhimurium. CPP, BF, and CPAA were roughly twice as mutagenic as benzo[a]pyrene (BaP), whereas CPAP was only slightly active. These PAHs were also tested for mutagenic activity in human cells. In this assay, CPP and CPAA were strongly mutagenic but less active than BaP, whereas CPAP and BF were inactive at the dose levels tested. Also, the bacterial and human cell mutagenicity of CPAA and CPAP were compared with the mutagenicity of their monocyclopenta-fused analogs, aceanthrylene and acephenanthyrlene. Although the mutagenicities of CPAP and acephenanthrylene are similar, the mutagenic activity of CPAA is an order of magnitude greater than that of aceanthyrlene. PMID:8354201

Human Pose Estimation from Monocular Images: A Comprehensive Survey

PubMed Central

Gong, Wenjuan; Zhang, Xuena; Gonzàlez, Jordi; Sobral, Andrews; Bouwmans, Thierry; Tu, Changhe; Zahzah, El-hadi

2016-01-01

Human pose estimation refers to the estimation of the location of body parts and how they are connected in an image. Human pose estimation from monocular images has wide applications (e.g., image indexing). Several surveys on human pose estimation can be found in the literature, but they focus on a certain category; for example, model-based approaches or human motion analysis, etc. As far as we know, an overall review of this problem domain has yet to be provided. Furthermore, recent advancements based on deep learning have brought novel algorithms for this problem. In this paper, a comprehensive survey of human pose estimation from monocular images is carried out including milestone works and recent advancements. Based on one standard pipeline for the solution of computer vision problems, this survey splits the problem into several modules: feature extraction and description, human body models, and modeling methods. Problem modeling methods are approached based on two means of categorization in this survey. One way to categorize includes top-down and bottom-up methods, and another way includes generative and discriminative methods. Considering the fact that one direct application of human pose estimation is to provide initialization for automatic video surveillance, there are additional sections for motion-related methods in all modules: motion features, motion models, and motion-based methods. Finally, the paper also collects 26 publicly available data sets for validation and provides error measurement methods that are frequently used. PMID:27898003
The effects of pre-incubation period and norharman on the mutagenic potency of 4-dimethylaminoazobenzene and 3'-methyl-4-dimethylaminoazobenzene in S. typhimurium.

PubMed

Lefevre, P A; Ashby, J

1981-01-01

The effects of the co-mutagen norharman on the mutagenicity of the rodent liver carcinogens 4-dimethyl-aminoazobenzene (DAB) and 3'-methyl-4-dimethyl-aminoazobenzene (3'-MeDAB) have been evaluated using the Ames Salmonella mutation assay. A period of pre-incubation was found to be necessary in order to detect DAB as a mutagen and to increase the initially weak response observed for 3'MeDAB; maximum responses were seen after 1 h pre-incubation in each case. The co-mutagenic properties of norharman were at their maximum for both azo-dyes in the direct plate-incorporation assay. Pre-incubation of either compound with norharman for increasing periods of time resulted in a decrease in potentiation, until after 1 h, an inhibition of mutagenicity was observed.
Changes in mutagenicity of protein pyrolyzates by reaction with nitrite.

PubMed

Yoshida, D; Matsumoto, T

1978-09-01

Pyrolyzates of protein and related materials were treated with nitrite under acidic conditions, and the mutagenic activity toward Salmonella tester strains was determined. After treatment with nitrite in acidic solution, casein pyrolyzate, an extract of roasted chicken meat, tobacco-smoke condensate and some aromatic amines showed appreciable decreases in their mutagenic activities toward Salmonella typhimurium TA 98. Aromatic amines in the pyrolyzates may be changed by nitrite treatment to other forms having no or lower mutagenic activity toward Salmonella typhimurium TA 98. The contribution by aromatic amines to the total mutagenic activity of the pyrolyzates was as high as 80% in both casein pyrolyzate and extract of roasted chicken meat and 50% in tobacco-smoke condensate. Pyrolyzates of protein and related materials did not show a decrease in the mutagenic activity toward Salmonella typhimurium TA 100 with the same treatment.
Mutagens from the cooking of food. III. Survey by Ames/Salmonella test of mutagen formation in secondary sources of cooked dietary protein.

PubMed

Bjeldanes, L F; Morris, M M; Felton, J S; Healy, S; Stuermer, D; Berry, P; Timourian, H; Hatch, F T

1982-08-01

A survey of mutagen formation during the cooking of a variety of protein-rich foods that are minor sources of protein intake in the American diet is reported (see Bjeldanes, Morris, Felton et al. (1982) for survey of major protein foods). Milk, cheese, tofu and organ meats showed negligible mutagen formation except following high-temperature cooking for long periods of time. Even under the most extreme conditions, tofu, cheese and milk exhibited fewer than 500 Ames/Salmonella typhimurium revertants/100 g equivalents (wet weight of uncooked food), and organ meats only double that amount. Beans showed low mutagen formation after boiling and boiling followed by frying (with and without oil). Only boiling of beans followed by baking for 1 hr gave appreciable mutagenicity (3650 revertants/100g equivalents). Seafood samples gave a variety of results: red snapper, salmon, trout, halibut and rock cod all gave more than 1000 revertants/100 g wet weight equivalents when pan-fried or griddle-fried for about 6 min/side. Baked or poached rock and deep-fried shrimp showed no significant mutagen formation. Broiled lamb chops showed mutagen formation similar to that in red meats tested in the preceding paper: 16,000 revertants/100 g equivalents. These findings show that as measured by bioassay in S. typhimurium, most of the foods that are minor sources of protein in the American diet are also minor sources of cooking-induced mutagens.
Regularization techniques for backward--in--time evolutionary PDE problems

NASA Astrophysics Data System (ADS)

Gustafsson, Jonathan; Protas, Bartosz

2007-11-01

Backward--in--time evolutionary PDE problems have applications in the recently--proposed retrograde data assimilation. We consider the terminal value problem for the Kuramoto--Sivashinsky equation (KSE) in a 1D periodic domain as our model system. The KSE, proposed as a model for interfacial and combustion phenomena, is also often adopted as a toy model for hydrodynamic turbulence because of its multiscale and chaotic dynamics. Backward--in--time problems are typical examples of ill-posed problem, where disturbances are amplified exponentially during the backward march. Regularization is required to solve such problems efficiently and we consider approaches in which the original ill--posed problem is approximated with a less ill--posed problem obtained by adding a regularization term to the original equation. While such techniques are relatively well--understood for linear problems, they less understood in the present nonlinear setting. We consider regularization terms with fixed magnitudes and also explore a novel approach in which these magnitudes are adapted dynamically using simple concepts from the Control Theory.
Student-Posed Problems

NASA Astrophysics Data System (ADS)

Harper, Kathleen A.; Etkina, Eugenia

2002-10-01

As part of weekly reports,1 structured journals in which students answer three standard questions each week, they respond to the prompt, If I were the instructor, what questions would I ask or problems assign to determine if my students understood the material? An initial analysis of the results shows that some student-generated problems indicate fundamental misunderstandings of basic physical concepts. A further investigation explores the relevance of the problems to the week's material, whether the problems are solvable, and the type of problems (conceptual or calculation-based) written. Also, possible links between various characteristics of the problems and conceptual achievement are being explored. The results of this study spark many more questions for further work. A summary of current findings will be presented, along with its relationship to previous work concerning problem posing.2 1Etkina, E. Weekly Reports;A Two-Way Feedback Tool, Science Education, 84, 594-605 (2000). 2Mestre, J.P., Probing Adults Conceptual Understanding and Transfer of Learning Via Problem Posing, Journal of Applied Developmental Psychology, 23, 9-50 (2002).
Ill Posed Problems: Numerical and Statistical Methods for Mildly, Moderately and Severely Ill Posed Problems with Noisy Data.

DTIC Science & Technology

1980-02-01

to estimate f -..ell, -noderately ,-ell, or- poorly. 1 ’The sansitivity *of a rec-ilarized estimate of f to the noise is made explicit. After giving the...AD-A 7 .SA92 925 WISCONSIN UN! V-MADISON DEFT OF STATISTICS F /S 11,’ 1 ILL POSED PRORLEMS: NUMERICAL ANn STATISTICAL METHODS FOR MILOL-ETC(U FEB 80 a...estimate f given z. We first define the 1 intrinsic rank of the problem where jK(tit) f (t)dt is known exactly. This 0 definition is used to provide insight
MUTAGENIC AND CLASTOGENIC PROPERTIES OF 3-CHLORO-4-(DICHLOROMETHYL)-5-HYDROXY-2(5H)-FURANONE: A POTENT BACTERIAL MUTAGEN IN DRINKING WATER

EPA Science Inventory

3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) was found to be a direct-acting mutagen in the Ames test for strains TA1535, TA1538, TA92, TA97, TA98, TA100 and TA102. The highest mutagenic response (approximately 13,000 revertants/nmol) was seen in strain TA100. The TA...
Mutagenicity of edible palm oil on the Ghanaian market before and after repeated heating.

PubMed

Asare, George A; Okyere, Genevieve O; Asante, Matilda; Brown, Charles A; Santa, Sheila; Asiedu, Bernice

2013-12-01

Red palm oil produced in Ghana largely by village folks has never been tested for its mutagenic potential. The study aimed at determining the mutagenicity of high-energy heated red palm oil (RRPO) and refined, bleached imported palm oil (PO) on the Ghanaian market. Samples of RRPO and PO were 1× and 5× heated for 10 min at 180 °C with a cooling period of 5 h in-between. Unheated, together with heated samples, were tested for mutagenicity using Salmonella typhimurium TA 98 and TA 100 tester stains. Unheated PO was negative for the Ames mutagenicity test with TA 98 strain. However, 1× and 5× heated PO were mutagenic (P = 0.05, each). Testing PO, using TA 100 strain was negative. RRPO was mutagenic with TA 98 strain for heated oils (P = 0.05, each). Assays with TA 100 strain showed highly significant mutations (P = 0.001, each) that increased with increasing heating frequency. PO 1× and 5× heated samples caused significant frameshift mutation in the S. typhimurium TA 98 strain. RRPO caused highly significant point and frameshift mutations in heated samples. Furthermore, unheated RRPO mutagenic potential has serious health implications. © 2013 Institute of Food Technologists®
Estimation of the contribution of ultrafine particles to lung deposition of particle-bound mutagens in the atmosphere.

PubMed

Kawanaka, Youhei; Matsumoto, Emiko; Sakamoto, Kazuhiko; Yun, Sun-Ja

2011-02-15

The present study was performed to estimate the contributions of fine and ultrafine particles to the lung deposition of particle-bound mutagens in the atmosphere. This is the first estimation of the respiratory deposition of atmospheric particle-bound mutagens. Direct and S9-mediated mutagenicity of size-fractionated particulate matter (PM) collected at roadside and suburban sites was determined by the Ames test using Salmonella typhimurium strain TA98. Regional deposition efficiencies in the human respiratory tract of direct and S9-mediated mutagens in each size fraction were calculated using the LUDEP computer-based model. The model calculations showed that about 95% of the lung deposition of inhaled mutagens is caused by fine particles for both roadside and suburban atmospheres. Importantly, ultrafine particles were shown to contribute to the deposition of mutagens in the alveolar region of the lung by as much as 29% (+S9) and 26% (-S9) for the roadside atmosphere and 11% (+S9) and 13% (-S9) for the suburban atmosphere, although ultrafine particles contribute very little to the PM mass concentration. These results indicated that ultrafine particles play an important role as carriers of mutagens into the lung. Copyright © 2010 Elsevier B.V. All rights reserved.
Role of Mutagenicity in Asbestos Fiber-Induced Carcinogenicity and Other Diseases

PubMed Central

Huang, Sarah X. L.; Jaurand, Marie-Claude; Kamp, David W.; Whysner, John; Hei, Tom K.

2011-01-01

The cellular and molecular mechanisms of how asbestos fibers induce cancers and other diseases are not well understood. Both serpentine and amphibole asbestos fibers have been shown to induce oxidative stress, inflammatory responses, cellular toxicity and tissue injuries, genetic changes, and epigenetic alterations in target cells in vitro and tissues in vivo. Most of these mechanisms are believe to be shared by both fiber-induced cancers and noncancerous diseases. This article summarizes the findings from existing literature with a focus on genetic changes, specifically, mutagenicity of asbestos fibers. Thus far, experimental evidence suggesting the involvement of mutagenesis in asbestos carcinogenicity is more convincing than asbestos-induced fibrotic diseases. The potential contributions of mutagenicity to asbestos-induced diseases, with an emphasis on carcinogenicity, are reviewed from five aspects: (1) whether there is a mutagenic mode of action (MOA) in fiber-induced carcinogenesis; (2) mutagenicity/carcinogenicity at low dose; (3) biological activities that contribute to mutagenicity and impact of target tissue/cell type; (4) health endpoints with or without mutagenicity as a key event; and finally, (5) determinant factors of toxicity in mutagenicity. At the end of this review, a consensus statement of what is known, what is believed to be factual but requires confirmation, and existing data gaps, as well as future research needs and directions, is provided. PMID:21534089
Oxidative mutagenesis of doxorubicin-Fe(III) complex.

PubMed

Kostoryz, E L; Yourtee, D M

2001-02-20

Doxorubicin has a high affinity for inorganic iron, Fe(III), and has potential to form doxorubicin-Fe(III) complexes in biological systems. Indirect involvement of iron has been substantiated in the oxidative mutagenicity of doxorubicin. In this study, however, direct involvement of Fe(III) was evaluated in mutagenicity studies with the doxorubicin-Fe(III) complex. The Salmonella mutagenicity assay with strain TA102 was used with a pre-incubation step. The highest mutagenicity of doxorubicin-Fe(III) complex was observed at the dose of 2.5nmol/plate of the complex. The S9-mix decreased this highest mutagenicity but increased the number of revertants at a higher dose of 10nmol/plate of the complex. On the other hand, the mutagenicity of the doxorubicin-Fe(III) complex at the doses of 0.25, 0.5, 1 and 2nmol/plate was enhanced about twice by the addition of glutathione plus H(2)O(2). This enhanced mutagenicity as well as of the complex itself, the complex plus glutathione, and the complex plus H(2)O(2) were reduced by the addition of ADR-529, an Fe(III) chelator, and potassium iodide, a hydroxyl radical scavenger. These results indicate that doxorubicin-Fe(III) complex exert the mutagenicity through oxidative DNA damage and that Fe(III) is a required element in the mutagenesis of doxorubicin.
Evaluation of the cytotoxicity, genotoxicity, mutagenicity, and antimutagenicity of propolis from Tucuman, Argentina.

PubMed

Nieva Moreno, María I; Zampini, Iris C; Ordóñez, Roxana M; Jaime, Gloria S; Vattuone, Marta A; Isla, María I

2005-11-16

This study evaluates the toxic, genotoxic/mutagenic, and antimutagenic effects of propolis extract from Amaicha del Valle, Tucumán, Argentina. The cytotoxicity assays carried out with the lethality test of Artemia salina revealed that the LD50 was around 100 microg/mL. Propolis extracts showed no toxicity to Salmonella typhimurium TA98 and TA100 strains and Allium cepa at concentrations that have antibiotic and antioxidant activities. Otherwise, for the testing doses, neither genotoxicity nor mutagenicity was found in any sample. The propolis extracts were able to inhibit the mutagenesis of isoquinoline (IQ) and 4-nitro o-phenylenediamine (NPD) with ID50 values of 40 and 20 microg/plate, respectively. From this result, the studied propolis may be inferred to contain some chemical compounds capable of inhibiting the mutagenicity of direct-acting and indirect-acting mutagens. A compound isolated from Amaicha del Valle propolis, 2',4'-dihydroxychalcone, showed cytotoxic activity (LC50 values of 0.5 microg/mL) but was not genotoxic or mutagenic. Furthermore, this compound was able to inhibit the mutagenicity of IQ (ID50 values of 1 microg/plate) but was unable to inhibit the mutagenicity of NPD. Our results suggest a potential anticarcinogenic activity of Amaicha del Valle propolis and the chalcone isolated from it.
Screening complex hazardous wastes for mutagenic activity using a modified version of the TLC/Salmonella assay.

PubMed

Houk, V S; Claxton, L D

1986-03-01

10 complex hazardous wastes were tested for mutagenic activity using a modified version of the TLC/Salmonella assay developed by Bjørseth et al. (1982). This fractionation/bioassay scheme couples thin-layer chromatography (TLC) with the Salmonella/mammalian-microsome (Ames) assay for the detection of mutagenic constituents in complex mixtures. Crude (unadulterated) hazardous wastes and selected hazardous waste extracts were fractionated on commercially available cellulose TLC plates. Mutagenicity testing was performed in situ by applying a single overlay of minimal growth agar, tester strain TA98 or TA100, and the optional metabolic activation system directly onto the developed chromatogram. A mutagenic effect was indicated either by the appearance of localized clusters of revertant colonies or by an increase in total revertant growth vis-à-vis control plates. 7 of 10 hazardous wastes (including tars, emulsions, sludges, and spent acids and caustics) demonstrated mutagenic activity when tested by this method. To assess the sensitivity of the modified TLC/Salmonella assay, 14 Salmonella mutagens from a wide range of chemical classes and polarities were tested. Selected compounds included heterocyclics, aromatic amines, alkylating agents, antitumor agents, a nitrosamine and a nitroaromatic. 11 of the 14 mutagens were positive in this test system. The 3 compounds refractory to analysis included a polycyclic aromatic hydrocarbon and two volatiles.
Mutagenicity of arsenic in mammalian cells: role of reactive oxygen species

NASA Technical Reports Server (NTRS)

Hei, T. K.; Liu, S. X.; Waldren, C.

1998-01-01

Arsenite, the trivalent form of arsenic present in the environment, is a known human carcinogen that lacked mutagenic activity in bacterial and standard mammalian cell mutation assays. We show herein that when evaluated in an assay (AL cell assay), in which both intragenic and multilocus mutations are detectable, that arsenite is in fact a strong dose-dependent mutagen and that it induces mostly large deletion mutations. Cotreatment of cells with the oxygen radical scavenger dimethyl sulfoxide significantly reduces the mutagenicity of arsenite. Thus, the carcinogenicity of arsenite can be explained at least in part by it being a mutagen that depends on reactive oxygen species for its activity.
Characterization of mutagenic activity in grain-based coffee-substitute blends and instant coffees

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johansson, M.A.E.; Knize, M.G.; Felton, J.S.

1994-06-01

Several grain-based coffee-substitute blends and instant coffees showed a mutagenic response in the Ames/Salmonella test using TA98, YG1024 and YG1O29 with metabolic activation. The beverage powders contained 150 to 500 TA98 and 1150 to 4050 YG1024 revertant colonies/gram, respectively. The mutagenic activity in the beverage powders was shown to be stable to heat and the products varied in resistance to acid nitrite treatment. Characterization of the mutagenic activity, using HPLC-and the Ames test of the collected fractions, showed the coffee-substitutes and instant coffees contain several mutagenic compounds, which are most likely aromatic amines.
In-the-wild facial expression recognition in extreme poses

NASA Astrophysics Data System (ADS)

Yang, Fei; Zhang, Qian; Zheng, Chi; Qiu, Guoping

2018-04-01

In the computer research area, facial expression recognition is a hot research problem. Recent years, the research has moved from the lab environment to in-the-wild circumstances. It is challenging, especially under extreme poses. But current expression detection systems are trying to avoid the pose effects and gain the general applicable ability. In this work, we solve the problem in the opposite approach. We consider the head poses and detect the expressions within special head poses. Our work includes two parts: detect the head pose and group it into one pre-defined head pose class; do facial expression recognize within each pose class. Our experiments show that the recognition results with pose class grouping are much better than that of direct recognition without considering poses. We combine the hand-crafted features, SIFT, LBP and geometric feature, with deep learning feature as the representation of the expressions. The handcrafted features are added into the deep learning framework along with the high level deep learning features. As a comparison, we implement SVM and random forest to as the prediction models. To train and test our methodology, we labeled the face dataset with 6 basic expressions.
The mutagenicity of indoor air particles in a residential pilot field study: Application and evaluation of new methodologies

NASA Astrophysics Data System (ADS)

Lewtas, Joellen; Goto, Sumio; Williams, Katherine; Chuang, Jane C.; Petersen, Bruce A.; Wilson, Nancy K.

The mutagenicity of indoor air paniculate matter has been measured in a pilot field study of homes in Columbus, Ohio during the 1984 winter. The study was conducted in eight all natural-gas homes and two all electric homes. Paniculate matter and semi-volatile organic compounds were collected indoors using a medium volume sampler. A micro-forward mutation bioassay employing Salmonella typhimurium strain TM 677 was used to quantify the mutagenicity in solvent extracts of microgram quantities of indoor air particles. The mutagenicity was quantified in terms of both mutation frequency per mg of organic matter extracted and per cubic meter of air sampled. The combustion source variables explored in this study included woodburning in fireplaces and cigarette smoking. Homes in which cigarette smoking occurred had the highest concentrations of mutagenicity per cubic meter of air. The average indoor air mutagenicity per cubic meter was highly correlated with the number of cigarettes smoked. When the separate sampling periods in each room were compared, the mutagenicity in the kitchen samples was the most highly correlated with the number of cigarettes smoked.
Biochemical mutagens affect the preservation of fungi and biodiversity estimations.

PubMed

Paterson, R Russell M; Lima, Nelson

2013-01-01

Many fungi have significant industrial applications or biosafety concerns and maintaining the original characteristics is essential. The preserved fungi have to represent the situation in nature for posterity, biodiversity estimations, and taxonomic research. However, spontaneous fungal mutations and secondary metabolites affecting producing fungi are well known. There is increasing interest in the preservation of microbes in Biological Resource Centers (BRC) to ensure that the organisms remain viable and stable genetically. It would be anathema if they contacted mutagens routinely. However, for the purpose of this discussion, there are three potential sources of biochemical mutagens when obtaining individual fungi from the environment: (a) mixtures of microorganisms are plated routinely onto growth media containing mutagenic antibiotics to control overgrowth by contaminants, (b) the microbial mixtures may contain microorganisms capable of producing mutagenic secondary metabolites, and (c) target fungi for isolation may produce "self" mutagens in pure culture. The probability that these compounds could interact with fungi undermines confidence in the preservation process and the potential effects of these biochemical mutagens are considered for the first time on strains held in BRC in this review.
Ozonation of mutagenic and carcinogenic polyaromatic amines and polyaromatic hydrocarbons in water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burleson, G.R.; Caulfield, M.J.; Pollard, M.

1979-06-01

The Salmonella-microsome assay for mutagenesis was used to determine the effect of ozone on the mutagenesis of selected carcinogens and mutagens in water. Short periods of ozonation were shown to completely inactivate the mutagenicity of several polyaromatic amine mutagens including acriflavine, proflavine, and beta-naphthylamine. Selected polyaromatic hydrocarbons were also sensitive to ozonation. Kinetic studies revealed that the mutagenicity of benzo(a)pyrene, 3-methylcholanthrene, and 7,12-dimethylbenz(a)anthracene was destroyed after short periods of ozonation. To correlate loss of mutagenicity with loss of carcinogenicity, two polyaromatic hydrocarbons were treated with ozone, extracted from water with hexane, and tested for carcinogenicity in mice. When 7,12-dimethyl-benz(a)anthracene andmore » 3-methyl-cholanthrene were treated with ozone, there was a substantial reduction in carcinogenicity compared to control groups treated with oxygen alone. However, a small number of tumors developed in the group of animals receiving a hexane extract of ozonated 7,12-dimethylbenz(a)anthracene. This activity may be due to breakdown products of 7,12-dimethylbenz(a)anthracene that are not mutagenic.« less

Mutagenicity of burnt gun propellants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Felton, J.S.; Lewis, P.; Knize, M.G.

1989-08-02

The use of the Ames/Salmonella assay as a workplace monitoring method is a long-standing practice at LLNL. This practice has led to the discovery of very mutagenic soot in and around a 4 inch test gun. To the authors' knowledge this is the first finding of mutagenic components in the residue from gun propellants, although there have been numerous reports of mutagenic compounds associated with high explosives -- compounds of entirely different chemical composition (Won et al., 1976). In addition, Ase et al., 1985, analyzed the propellant combustion products of both a M16 rifle and a 105 mm caliber gunmore » with HPLC and GC/MS methods, and found a number of PAHs with known toxicological effects. No biological analysis was done on the residues. Further investigation in our laboratory found that direct acting mutagens where produced upon open burning of the propellants. Small gauge firearms when tested also showed mutagenic residue. Preliminary efforts to identify the mutagenic components estimate that 2-3 compounds are responsible for the biological activity. The identity of these compounds is under investigation. 8 refs., 4 tabs.« less
Mutagenicity in emissions from coal- and oil-fired boilers.

PubMed Central

Alfheim, I; Bergström, J G; Jenssen, D; Møller, M

1983-01-01

The mutagenicity of emission samples from three oil-fired and four coal-fired boilers have been compared by using the Salmonella/microsome assay. Very little or no mutagenic activity was observed in samples from five of these boilers. The sample from one oil-fired boiler showed mutagenic activity of about 500 revertants/MJ, and the sample from a coal-fired fluidized bed combustor had an activity of 58,000 revertants/MJ measured with strain TA 98 in the absence of metabolic activation. All samples contained substances that were cytotoxic to the test bacteria, thus making it difficult to obtain linear dose-response curves. Mutagenic activity at low levels may remain undetected due to this toxicity of the samples. Samples with mutagenic activity below the detection limit in the Salmonella test have also been tested for forward mutations at the HGPRT locus in V79 hamster cells. Weak mutagenic effects were detected in two of the samples, whereas the sample from one oil-fired boiler remained negative. In this test, as well as in the Salmonella test, a strong cytotoxic effect could be observed with all samples. PMID:6825617
Are All Ames Strains in the OECD Mutagenicity Test Guideline 471 Useful and Necessary? An Analysis of Large Mutagenicity Data Sets for the IWGT.

EPA Science Inventory

Are All Ames Strains in the OECD Mutagenicity Test Guideline 471 Useful and Necessary? An Analysis of Large Mutagenicity Data Sets for the IWGT R. Williams1, D.M. DeMarini2, L.F. Stankowski Jr.3, E. Zeiger4, K.P. Cross5 1Lhasa, LTD, Leeds, UK 2U.S. EPA, RTP, NC 3Charles River L...
Mutagenicity and human chromosomal effect of stevioside, a sweetener from Stevia rebaudiana Bertoni.

PubMed Central

Suttajit, M; Vinitketkaumnuen, U; Meevatee, U; Buddhasukh, D

1993-01-01

Leaves of Stevia rebaudiana Bertoni have been popularly used as a sweetener in foods and beverages for diabetics and obese people due to their potent sweetener stevioside. In this report, stevioside and steviol were tested for mutagenicity in Salmonella typhimurium strains TA98 and TA100 and for chromosomal effects on cultured human lymphocytes. Stevioside was not mutagenic at concentrations up to 25 mg/plate, but showed direct mutagenicity to only TA98 at 50 mg/plate. However, steviol did not exhibit mutagenicity in either TA98 or TA100, with or without metabolic activation. No significant chromosomal effect of stevioside and steviol was observed in cultured blood lymphocytes from healthy donors (n = 5). This study indicates that stevioside and steviol are neither mutagenic nor clastogenic in vitro at the limited doses; however, in vivo genotoxic tests and long-term effects of stevioside and steviol are yet to be investigated. PMID:8143647
Genotoxic potentials of lifestyles assessed by urinary mutagenicity.

PubMed

Mure, K; Morimoto, K

1994-09-01

The relationships between lifestyles and urinary mutagenicity were investigated by using blue rayon extraction from 33 healthy male workers' urine. Subjects were classified into three groups, as "good", "moderate", and "poor" according to their responses on a questionnaire regarding eight health practices (cigarette smoking, alcohol consumption, eating breakfast, hours of sleep, hours of work, physical exercise, caring about nutritional balance, mental stress). The better lifestyle groups exhibited the lower mutagenicity. Subjects in a "good" group showed significantly lower urinary mutagenicity than those both in a "moderate" (p < 0.05) and a "poor" (p < 0.05) groups at fraction number 1 to 3 that were given after ingesting fried beef. These tendencies also found at fraction number 8 to 9 that were given after smoking, although not significant. The lifestyles were significantly associated with the urinary mutagenicity, and the results suggested that not only particular lifestyle factor but also some combinations with smoking significantly enhanced with the urinary mutagenicity.
The Analysis of the Problems the Pre-Service Teachers Experience in Posing Problems about Equations

ERIC Educational Resources Information Center

Isik, Cemalettin; Kar, Tugrul

2012-01-01

The present study aimed to analyse the potential difficulties in the problems posed by pre-service teachers about first degree equations with one unknown and equation pairs with two unknowns. It was carried out with 20 pre-service teachers studying in the Department of Elementary Mathematics Educations at a university in Eastern Turkey. The…
Urinary excretion of mutagens in coke oven workers.

PubMed

Clonfero, E; Granella, M; Marchioro, M; Barra, E L; Nardini, B; Ferri, G; Foà, V

1995-03-01

The influence of occupational exposure to polycyclic aromatic hydrocarbons (PAHs) on urinary mutagenic activity was assessed in 75 coke oven workers, using a highly sensitive bacterial mutagen technique (extraction with C18 resin and liquid micro-preincubation test on strain TA98 of Salmonella typhimurium in the presence of metabolizing and deconjugating enzymes). Exposure to PAHs was assessed according to the urinary excretion of 1-pyrenol; the main confounding factors were checked by the number of cigarettes smoked per day and the levels of nicotine and its metabolites in urine, or by ascertaining whether recommended dietary restrictions had been followed. Of the 20 urine samples which turned out to be positive (producing at least double the number of spontaneous revertants), 19 (95%) belonged to smokers. Only one non-smoker had obvious urinary mutagenic activity, and was highly exposed occupationally to PAHs (urinary 1-pyrenol of 3.930 mumol/mol of creatinine). Of the five urine samples from subjects who had not followed the recommended diet, two (40%) were clearly mutagenic. Multiple regression analysis (n = 67) showed that the presence of samples positive for urinary mutagenic activity depended only on smoking habits, if this confounding factor was assessed according to the number of cigarettes smoked per day, while the significant influence of exposure to PAH could be shown when the confounding factor was objectively estimated according to the urinary levels of nicotine and its metabolites. Assessment of the mutagenic potency of urinary extracts (net revertants/mmol creatinine) confirmed the strong influence of smoking habits on urinary mutagenic activity (all smokers 2156 +/- 2691 versus non-smokers 939 +/- 947 net revertants/mmol creatinine; Mann-Whitney test: P < 0.01). In smokers highly exposed to PAHs, greater excretion of mutagens with respect to low-exposure smokers was revealed (3548 +/- 4009 versus 1552 +/- 1227 net revertants/mmol creatinine; Mann-Whitney test: P < 0.01). Multiple regression analysis showed that the mutagenic potency of urinary extracts of coke oven workers depended on exposure to PAHs, tobacco smoking habits, and consumption of fried, grilled or barbecued meat. Increased urinary mutagenic activity strengthens epidemiological evidence of the increased risk of renal and urinary tract tumours in these workers. The presence of mutagenic metabolites in urine as a result of occupational exposure to PAH may be demonstrated only by using highly sensitive techniques for assessing urinary mutagenic activity in studies which include careful checking of the main confounding factors.
Mutagenic activity and heterocyclic amine content of the human diet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knize, M.G.; Dolbeare, F.A.; Cunningham, P.L.

1993-01-15

The mutagenic activity and the mass amount of heterocyclic amines responsible for the mutagenic activity have been measured in some cooked foods. Cooked meats are the predominant source of mutagenic activity in the diet with values ranging from 0 to 10,000 revertants per gram reported in the Ames/Salmonelia test with strain TA98. Several heterocyclic amines are present and have been quantified using solid-phase extraction followed by HPLC. Frying at higher temperatures and for longer times produces the greatest mutagenic response, and concomitantly, the largest amounts of heterocyclic amines. Most of the mutagenic activity in fried meat samples can be accountedmore » for by MelQx, DiMelQx and IQ, although other heterocylic amines are present and PHIP mutagenic activity becomes significant at higher temperatures. Non-meat products such as baked breads can also form significant mutagenic activity, particularly when overcooked. Commercially prepared hamburgers made from meat substitutes such as tofu, wheat gluten or tempeh and fried at 210{degrees}C have up to 10% of the mutagenic activity of a fried beef patty cooked under the same conditions. When detected, amounts of heterocyclic amines in fried beef patties range from a total of 0.35 ng/g for commercial beef hamburgers to 142 ng/g for a beef patty cooked over a barbecue. Dietary intake is expected to have a large range, from less than one microgram per day to over 50 micrograms per day based on current knowledge of known heterocyclic amine chemicals and heterocyclic amine-containing foods.« less
Food mutagens: The role of cooked food in genetic changes

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-07-01

Of all the toxic substances producing during cooking, the most important are likely to be the heterocyclic amines. For 17 years, LLNL researchers have been identifying these food mutagens, measuring their abundance in cooked foods typical of the Western diet, working to understand how they can trigger malignant tumors in laboratory animals that have been exposed to high mutagen doses, and estimating the importance of human exposures. Our success is largely a function of the interdisciplinary approach we have taken to quantify food mutagens and to study their biological effects. LLNL investigators were the first to identify five of themore » most important mutagens in heated food, including PhIP and DiMeIQx. We have shown that fried beef may be the most important single source of heterocyclic amines in the human diet and the PhIP accounts for most of the combined mass of mutagens in fried beef cooked well-done. Most nonmeat foods contain low or undetectable levels of these types of compounds, but some cooked protein-containing foods, such as those high in wheat gluten, have significant levels of unknown aromatic amine mutagens. Cooking time and temperature significantly affect the amounts of mutagens generated. For example, reducing the frying temperature of ground beef from 250 to 200{degrees}C lowers the mutagenic activity by six- to sevenfold. Microwave pretreatment of meat and discarding the liquid that is formed also greatly reduces the formation of heterocyclic amines. Our related work on dose and risk assessment will be described in a forthcoming article.« less
Mutagenic activities of biochars from pyrolysis.

PubMed

Piterina, Anna V; Chipman, J Kevin; Pembroke, J Tony; Hayes, Michael H B

2017-08-15

Biochar production, from pyrolysis of lignocellulosic feedstocks, agricultural residues, and animal and poultry manures are emerging globally as novel industrial and commercial products. It is important to develop and to validate a series of suitable protocols for the ecological monitoring of the qualities and properties of biochars. The highly sensitive Salmonella mutagenicity assays (the Ames test) are used widely by the toxicology community and, via the rat liver extract (S9), can reflect the potential for mammalian metabolic activation. We examined the Ames test for analyses of the mutagenic activities of dimethylsulphoxide (DMSO) extracts of biochars using two bacterial models (S. typhimurium strains TA98 and TA100) in the presence and in the absence of the metabolic activation with the S9-mix. Tester strain TA98 was most sensitive in detecting mutagenic biochar products, and the contribution of S9 was established. Temperature and times of pyrolysis are important. Biochar pyrolysed at 400°C for 10min, from a lignocellulose precursor was mutagenic, but not when formed at 800°C for 60min, or at 600°C for 30min. Biochars from poultry litter, and manures of calves fed on grass had low mutagenicities. Biochar from pig manure had high mutagenicity; biochars from manures of cows fed on a grass plus cereals, those of calves fed on mother's milk, and biochars from solid industrial waste had intermediate mutagenicities. The methods outlined can indicate the need for further studies for screening and detection of the mutagenic residuals in a variety of biochar products. Copyright © 2017. Published by Elsevier B.V.
Control and System Theory, Optimization, Inverse and Ill-Posed Problems

DTIC Science & Technology

1988-09-14

Justlfleatlen Distribut ion/ Availability Codes # AFOSR-87-0350 Avat’ and/or1987-1988 Dist Special *CONTROL AND SYSTEM THEORY , ~ * OPTIMIZATION, * INVERSE...considerable va- riety of research investigations within the grant areas (Control and system theory , Optimization, and Ill-posed problems]. The
Gender differences in the metabolism of 1,3-butadiene to butadiene diepoxide in Sprague-Dawley rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thornton-Manning, J.R.; Dahl, A.R.; Bechtold, W.E.

1995-12-01

1,3-Butadiene (BD), a gaseous compound used in the production of rubber, is a potent carcinogen in mice and a weak carcinogen in rats. The mechanism of BD-induced carcinogenicity is thought to involve genotoxic effects of its reactive epoxide metabolites butadiene monoepoxide (BDO) and butadiene diepoxide (BDO{sub 2}). Studies in our laboratory have shown that levels of the epoxides, particularly BDO{sub 2}, are greater in mice-the more sensitive species-than rats. While both epoxides are genotoxic in a number of assays, BDO{sub 2} is mutagenic in TK6 human lymphoblastoid cells at concentrations approximately 100-fold lower than BDO. Species differences in carcinogenicity ofmore » BD have posed a dilemma to investigators deciding which animal model is most appropriate for BD risk assessment.« less
Mutagenicity of pan residues and gravy from fried meat.

PubMed

Overvik, E; Nilsson, L; Fredholm, L; Levin, O; Nord, C E; Gustafsson, J A

1987-02-01

Lean pork meat was fried with or without the addition of frying-fat at 200 or 250 degrees C. The pan residues were collected by washing the hot pan with boiling water. When producing thickened gravy the water was substituted by a mixture of water and flour, milk and flour or cream and flour. The basic extracts were tested for mutagenicity in Ames' Salmonella test on strain TA98 with the addition of S9 mix. High amounts of mutagenicity were found in all samples. The amounts of mutagenicity in the pan residues were at a comparable level of the amounts found in the meat crusts. Thickening of the gravy caused only small changes in the mutagenicity.
Mutagenic Potential of p-Dithiane.

DTIC Science & Technology

1985-08-01

UNCLASSIFIED FGO 6/29 M 01. JLt * L, mia -l En.25 .4 166 MICROCOP RESOUTION TEST CHART an INSTITUTE REPORT NO. 207 LEC 10 MA20 I--- co DTI ( MUTAGENIC...mg/plate to 0.0016 mg/plate. The test compound was not mutagenic under conditions of this assay. Key Words: Mutagenicity, Genetic Toxicology, Ames...aliquot of the test compound will be retained in the LAIR Archives. TEST SUBSTANCE: p-Dithiane (TA039) INCLUSIVE STUDY DATES: 24 September - 12 October
2,3,7,8 tetrachlorodibenzodioxin in fish from the Pigeon river of Eastern Tennessee: Its toxicity and mutagenicity as revealed by the Ames Salmonella Assay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blevins, R.D.

1990-04-01

Levels of 2,3,7,8 tetrachlorodibenzodioxin (TCDD)were determined in both striated muscle (fillets) and whole body extracts of fish specimens harvested during a two year period (1987-1989) from the Pigeon River (between Hartford and Newport) of Eastern Tennessee. Whole body (wet weight) fish extract levels as high as 117 {mu}g/kg body weight and composite fish fillet (wet weight) extract levels as high 87 {mu}g/kg fillet weight were observed. Pure TCDD was found to be highly toxic to the Salmonella typhimurium strains TA97, TA98, TA100, TA102 and TA1535 at TCDD dosages which exceeded 825 ng/ml in the top agar of the Ames Salmonellamore » assay. An 825 ng/ml TCDD dosage was not mutagenic to any of the tested Salmonella strains, (both with and without metabolic activation (S9) mix). However, when both acidic and alcohol fish extracts from the Pigeon River were tested for mutagenicity, several of the fish extracts were found to be mutagenic to Salmonella strains TA97, TA98, and TA100 (having mutagenic ratios which greatly exceeded the 2.5 {times} spontaneous ratio). These mutagenic extracts also demonstrated mutagenic dose-response curves. Other chemicals within the extracts as well as synergistic effects may account for the mutagenicity.« less
Biological activity of particle exhaust emissions from light-duty diesel engines.

PubMed

Carraro, E; Locatelli, A L; Ferrero, C; Fea, E; Gilli, G

1997-01-01

Whole diesel exhaust has been classified recently as a probable carcinogen, and several genotoxicity studies have found particulate exhaust to be clearly mutagenic. Moreover, genotoxicity of diesel particulate is greatly influenced by fuel nature and type of combustion. In order to obtain an effective environmental pollution control, combustion processes using alternative fuels are being analyzed presently. The goal of this study is to determine whether the installation of exhaust after treatment-devices on two light-duty, exhaust gas recirculation (EGR) valve-equipped diesel engines (1930 cc and 2500 cc) can reduce the mutagenicity associated with particles collected during U.S.A. and European driving cycles. Another interesting object was to compare the ability of alternative biodiesel and conventional diesel fuels to reduce the mutagenic activity associated with collected particles from two light duty diesel engines (both 1930 cc) during the European driving cycle. SOF mutagenicity was assayed using the Salmonella/microsome test (TA 98 and TA 100 strains, +/- S9 fraction). In the first part of our study, the highest mutagenicity was revealed by TA98 strain without enzymatic activation, suggesting a direct-acting mutagenicity prevalence in diesel particulate. The 2500 cc engine revealed twofold mutagenic activity compared with the 1930 cc engine (both EGR valve equipped), whereas an opposite result was found in particulate matter amount. The use of a noncatalytic ceramic trap produced a decrease of particle mutagenic activity in the 2500 cc car, whereas an enhancement in the 1930 cc engine was found. The catalytic converter and the electrostatic filter installed on the 2500 cc engine yielded a light particle amount and an SOF mutagenicity decrease. A greater engine stress was obtained using European driving cycles, which caused the strongest mutagenicity/km compared with the U.S.A. cycles. In the second part of the investigation, even though a small number of assays were available, exhaust emission generation by biodiesel fuel seemed to yield a smaller environmental impact than that of the referenced diesel fuel. The results point out the usefulness of mutagenicity testing in the research of both newer, more efficient automotive aftertreatment devices and less polluting fuels.
Seasonal and spatial variation of the bacterial mutagenicity of fine organic aerosol in southern california.

PubMed Central

Hannigan, M P; Cass, G R; Lafleur, A L; Busby, W F; Thilly, W G

1996-01-01

The bacterial mutagenicity of a set of 1993 urban particulate air pollution samples is examined using the Salmonella typhimurium TM677 forward mutation assay. Amibent fine particulate samples were collected for 24 hr every sixth day throughout 1993 at four urban sites, including Long Beach, central Los Angeles, Azusa, and Rubidoux, California, and at an upwind background site on San Nicolas Island. Long Beach and central Los Angeles are congested urban areas where air quality is dominated by fresh emissions from air pollution sources; Azuasa and Rubidoux are located farther downwind and receive transported air pollutants plus increased quantities of the products of atmospheric chemical reactions. Fine aerosol samples from Long Beach and Los Angeles show a pronounced seasonal variation in bacterial mutagenicity per cubic meter of- ambient air, with maximum in the winter and a minimum in the summer. The down-wind smog receptor site at Rubidoux shows peak mutagenicity (with postmitochondrial supernatant but no peak without postmitochondrial supernatant) during the September-October periods when direct transport from upwind sources can be expected. At most sites the mutagenicity per microgram of organic carbon from the aerosol is not obviously higher during the summer photochemical smog period than during the colder months. Significant spatial variation in bacterial mutagenicity is observed: mutagenicity per cubic meter of ambient air, on average, is more than an order of magnitude lower at San Nicolas Island than within the urban area. The highest mutagenicity values per microgram of organics supplied to the assay are found at the most congested urban sites at central Los Angeles and Long Beach. The highest annual average values of mutagenicity per cubic meter of air sampled occur at central Los Angeles. These findings stress the importance of proximity to sources of direct emissions of bacterial mutagens and imply that if important mutagen-forming atmospheric reactions occur, they likely occur in the winter and spring seasons as well as the photochemically more active summer and early fall periods. Images Figure 1. Figure 2. Figure 2. Figure 2. Figure 2. Figure 3. Figure 3. Figure 4. Figure 5. Figure 6. PMID:8732954
THE GENOTOXICITY OF AMBIENT OUTDOOR AIR, A REVIEW: SALMONELLA MUTAGENICITY

EPA Science Inventory

The genotoxicity of ambient outdoor air, a review: Salmonella mutagenicity

Abstract
Mutagens in urban air pollution come from anthropogenic sources (especially combustion sources) and are products of airborne chemical reactions. Bacterial mutation tests have been used ...
Mutagenicity of Cookstove Emissions

EPA Science Inventory

The presentation by David DeMarini will focus on emission factors, including mutagenicity, for 3 stoves. It will correlate the emission factors to assess the health safety of the stove systems and place the mutagenicity emission factor in context with that of other combustion em...
The role of cytogenetic tests in detection and prevention of cancer.

PubMed

Bishun, N P

1981-01-01

Although simplified and improved techniques have increased at a fast rate in recent years, a great number of compounds released into our environment still remain untested. It has been estimated that between 80-90% of human cancer is a result of exposure to such compounds, and if by the application of short-term mutagenic tests, the use of many of these compounds can be severely restricted, an enormous impact can be made on the solution of human health problems. Batteries of mutagenic tests have established an empirical relationship between mutagenisis and carcinogenisis, and, in view of the cost in terms of time and money, short-term tests are playing an important role in first detecting, and second, eliminating potential hazards in our environment. The use of bacteria and other unicellular organisms in these assay systems has met with much criticism; due to the fact that the DNA materials affected do not directly relate to that of man. However, in conjunction with other tests, utilizing human and other mammalian cells, firm conclusions can be drawn regarding the potential hazards of certain chemicals. Recent advances in cytogenetic tests (e.g., banding chromosomes and sister chromatid exchange) have improved the sensitivity of chromosomal tests and, in so doing, have rendered them more usual in the selecting out process that can reduce substantially the mutagenic and carcinogenic hazards caused by chemicals and other deleterious agents in the environment.

Determination of the mutagenic and genotoxic potential of simulated leachate from an automobile workshop soil on eukaryotic system.

PubMed

Alabi, Okunola Adenrele; Omosebi, Omotoyosi; Chizea, Ifychukwwu

2015-07-01

Contamination of soil and water bodies with spent engine oil and petroleum products is a serious ecological problem, primarily in the automobile workshops and garages. This has potential short and chronic adverse health risks. Information is currently scarce on the potential mutagenicity and genotoxicity of such wastes. In this study, the potential mutagenic and genotoxic effects of simulated leachate from automobile workshop soil in Sagamu, Ogun state, Nigeria, were investigated. The assays utilized were bone marrow micronucleus (MN) and chromosome aberration (CA), sperm morphology and sperm count in mice. The physicochemical analysis of the leachate was also carried out. Experiments were carried out at concentrations of 1, 5, 10, 25, 50, 75 and 100% (volume per volume; leachate:distilled water) of the leachate sample. MN analysis showed a concentration-dependent induction of micronucleated polychromatic erythrocytes across the treatment groups. In the CA test, there was concentration-dependent significant reduction in mitotic index and induction of different types of CAs. Assessment of sperm shape showed a significant increase in sperm abnormalities with significant decrease in mean sperm count in treated groups. Heavy metals analyzed in the tested sample are believed to contribute significantly to the observed genetic damage. This indicates that automobile workshop soil-simulated leachate contains potential genotoxic agents and constitutes a genetic risk in exposed human population. © The Author(s) 2013.
The World in a Tomato: Revisiting the Use of "Codes" in Freire's Problem-Posing Education.

ERIC Educational Resources Information Center

Barndt, Deborah

1998-01-01

Gives examples of the use of Freire's notion of codes or generative themes in problem-posing literacy education. Describes how these applications expand Freire's conceptions by involving students in code production, including multicultural perspectives, and rethinking codes as representations. (SK)
Assessment of a Problem Posing Task in a Jamaican Grade Four Mathematics Classroom

ERIC Educational Resources Information Center

Munroe, Kayan Lloyd

2016-01-01

This paper analyzes how a teacher of mathematics used problem posing in the assessment of the cognitive development of 26 students at the grade-four level. The students, ages 8 to 10 years, were from a rural elementary school in western Jamaica. Using a picture as a prompt, students were asked to generate three arithmetic problems and to offer…
Assessment of Cellular Mutagenicity of Americano Coffees from Popular Coffee Chains.

PubMed

Liu, Zhen-Shu; Chen, Po-Wen; Wang, Jung-Yu; Kuo, Tai-Chen

2017-09-01

Coffee is a popular beverage worldwide, but coffee beans can be contaminated with carcinogens. The Ames Salmonella mutagenicity test is often used for analysis of carcinogens for mutagenicity. However, previous studies have provided controversial data about the direct mutagenicity of coffee beans based on Ames test results. This study was conducted to determine the mutagenicity of popular Americano coffee based on results from the Ames test. Coffee samples without additives that were served by five international coffee chain restaurants were subjected to the analysis using Salmonella Typhimurium tester strains TA98, TA100, and TA1535. The levels of bacterial revertants in samples from coffee chains were lower than the twofold criterion of the control sets, and no significant dose-response effect was observed with or without rat liver enzyme activation. These data indicate that Americano coffees from the selected coffee chains possessed no direct mutagenic activity with or without enzyme activation. These findings suggest a low mutagenic risk from Americano coffees served by the selected coffee chains and support the use of other methods to confirm the nonmutagenicity of coffee products. These results are consistent with most recent epidemiological reports.
Ten factors for considering the mode of action of Cr(VI)-induced gastrointestinal tumors in rodents.

PubMed

Thompson, Chad M; Suh, Mina; Proctor, Deborah M; Haws, Laurie C; Harris, Mark A

2017-11-01

The determination of whether a chemical induces a specific cancer through a mutagenic or non-mutagenic mode of action (MOA) plays an important role in choosing between linear and nonlinear low-dose extrapolation to derive toxicity criteria. There is no formal framework from the U.S. EPA for determining whether environmental chemicals act through a mutagenic or non-mutagenic MOA; consequently, most such determinations are made on an ad hoc basis. Eastmond [Mutat Res 751 (2012)] recently conducted a systematic investigation of MOA determinations by U.S. and international regulatory agencies and organizations, and identified ten major factors that influence them, including toxicokinetics, in vivo genotoxicity in target organs, data quality, and evidence for alternative MOAs. We have used these ten factors to evaluate mutagenic vs. non-mutagenic MOA for gastrointestinal tumors induced by oral exposure to hexavalent chromium [Cr(VI)]. We also highlight similarities between Cr(VI) and other intestinal carcinogens previously determined to have non-genotoxic MOAs. Based on these analyses, we conclude that the MOA for Cr(VI) induced gastrointestinal tumors is non-mutagenic and that threshold risk assessment approaches are appropriate. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.
METHODS FOR THE SPIRAL SALMONELLA MUTAGENICITY ASSAY INCLUDING SPECIALIZED APPLICATIONS

EPA Science Inventory

ABSTRACT

An automated approach to bacterial mutagenicity testing--the spiral Salmonella assay--was developed to simplify testing and to reduce the labor and materials required to generate dose-responsive mutagenicity information. This document provides the reader with an ...
GENERAL ENHANCEMENT OF MUTAGENIC POTENCY OF VARIOUS MUTAGENS DUE TO DELETED GENES IN THE ΔuvrB STRAINS TA 98 AND TA 100 OF SALMONELLA COMPARED WITH STRAINS CONTAINING ONLY A POINT MUTATION IN uvrB

EPA Science Inventory

The two most common strains used in Ames mutagenicity assays, TA98 and TA 100, contain a �uvrB mutation designed to enhance the mutagenicity of compounds, presumably due to the loss of the nucleotide excision repair system. We showed previously that the �uvrB mutations in these s...
Mutagenic activity and heterocyclic amine content of heated foods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knize, M.G.; Johansson, M.; Jones, A.L.

1994-12-31

Cooked foods were extracted and analyzed for mutagenic activity and assayed for known heterocyclic amines (HAs) by the Ames/Salmonella test and HPLC, respectively. Fried meats contain HAs (predominantly PhIP, MeIQx, DiMeIQx, and A{alpha}C) that are potent promutagens in bacteria, mutagenic in cultured mammalian cells, and carcinogenic in rodents and in nonhuman primates. Meats contain levels ranging from undetectable (< 0.1 ppb) to 50 ppb of known HAs when fried at temperatures from 190 to 250{degrees}C. These identified compounds are responsible for ca 75% of the measured mutagenic activity in Salmonella strain TA98. Barbecued beef and chicken have up to severalmore » thousand TA98 revertants per gram (rev/g) of cooked meat, with only ca 30% of the mutagenic activity accounted for by known heterocyclic amines. Some heated nonmeat foods also contain potent mutagenic activity. Toasted breads, cereals and snack foods have 0 to 10 TA98 rev/g, but overtoasting yields up to 40 rev/g, wheat and gluten-containing products are associated with higher activity. Grain-based coffee-substitute powders and instant coffees have 190 to 380 rev/g in TA98, and 1100 to 4000 rev/g in strain YG1024. The identify of the compounds responsible for the mutagenic activity are unknown in these non-meat foods. Toasted grain-based foods probably contribute less than 10% of the total mutagenic activity of the diet, with meat products responsible for the reminder. The finding of varying amounts of known and unknown mutagens in some cooked foods may be responsible for the poorly understood variation in human cancer incidence worldwide.« less
Mutagenicity of an aged gasworks soil during bioslurry treatment

PubMed Central

Lemieux, Christine L; Lynes, Krista D; White, Paul A; Lundstedt, Staffan; Öberg, Lars; Lambert, Iain B

2009-01-01

This study investigated changes in the mutagenic activity of organic fractions from soil contaminated with polycyclic aromatic hydrocarbons (PAHs) during pilot-scale bioslurry remediation. Slurry samples were previously analyzed for changes in PAH and polycyclic aromatic compound content, and this study examined the correspondence between the chemical and toxicological metrics. Nonpolar neutral and semipolar aromatic fractions of samples obtained on days 0, 3, 7, 24, and 29 of treatment were assayed for mutagenicity using the Salmonella mutation assay. Most samples elicited a significant positive response on Salmonella strains TA98, YG1041, and YG1042 with and without S9 metabolic activation; however, TA100 failed to detect mutagenicity in any sample. Changes in the mutagenic activity of the fractions across treatment time and metabolic activation conditions suggests a pattern of formation and transformation of mutagenic compounds that may include a wide range of PAH derivatives such as aromatic amines, oxygenated PAHs, and S-heterocyclic compounds. The prior chemical analyses documented the formation of oxygenated PAHs during the treatment (e.g., 4-oxapyrene-5-one), and the mutagenicity analyses showed high corresponding activity in the semipolar fraction with and without metabolic activation. However, it could not be verified that these specific compounds were the underlying cause of the observed changes in mutagenic activity. The results highlight the need for concurrent chemical and toxicological profiling of contaminated sites undergoing remediation to ensure elimination of priority contaminants as well as a reduction in toxicological hazard. Moreover, the results imply that remediation efficacy and utility be evaluated using both chemical and toxicological metrics. Environ. Mol. Mutagen. 2009. © 2009 Wiley-Liss, Inc. PMID:19274766
Interlaboratory comparison of mutagenesis testing of coal fly ash derived from differenct coal conversion technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chrisp, C.; Hobbs, C.; Clark, R.

1979-01-01

This experiment showed that mutagenicity of fly ash derived from different coal conversion technologies, as determined by the Ames plate incorporation test, was similar in all three laboratories. The differences in mutagenic activity of each fly ash between laboratories with different solvent extraction methods were no greater than one order of magnitude. In addition, there were much smaller, but still significant differences in mutagenic activity between laboratories when the same solvent extract of a particular fly ash was tested in each laboratory. There were also significant differences in mutagenicity of the positive control mutagen (maximum of fivefold) between laboratories. Becausemore » of this difference in Ames test sensitivity between laboratories, the influence of the solvent extraction methods on differences in mutagenicity was not clear. However, the data suggested that either there were significant differences in the degree of sensitivity of Ames tests for different complex mixtures within each laboratory, or else there were differences in mutagen extraction efficiency between different solvent extraction methods. Both Ames test sensitivity and solvent extraction may be important. Further work would be necessary to separate the contribution of these two factors. An important aspect of further work would be to separate the contribution of the innate sensitivity of substrains of Ames tester strains in each laboratory from the possible effects of differences in Ames testing methodology. This could be done by testing the same extracts of fly ash and positive control mutagens with substrains of tester strains exchanged between laboratories. This work also implies that caution should be exercised in assuming that the same solvent would have the same efficiency for extraction of mutagens from different fly ashes even within the same laboratory.« less
Mutagenicity and Nitropyrene Concentration of Indoor Air Particulates Exhausted from a Kerosene Heater*1

PubMed Central

Kinouchi, Takemi; Nishifuji, Keiko; Tsutsui, Hideshi; Hoare, Sadako Louise

1988-01-01

The particulates in a room warmed with a radiant kerosene heater were collected, extracted and fractionated into diethyl ether‐soluble neutral, acidic and basic fractions. The mutagenicity of these fractions was measured with Salmonella typhimurium strains TA98, TA98NR, TA98/1,8‐DNP6 and TA100 in the presence and ahsence of S9 mix. Room air without the heater showed very low mutagenicity. However, a sample from a room at the beginning of the burning period showed very high mutagenicity (237 His+ revertants/plate/m*3 of air in strain TA98 in the absence of S9 mix). In contrast, emissions from the heater after it was burning stably showed low mutagenicity (9 His+ revertants/plate/m*3). The crude extract of particulates from the heater at the beginning of the burning period was analyzed by high‐pressure liquid chromatography (HPLC) and showed a considerable amount of nitropyrenes (NPs); the concentrations of 1‐NP and 1,6‐diNP were 1.62 ng and 0.149 ng/m*3 of air, respectively, and accounted for 1.2% and 17.6%, respectively, of the mutagenicity in strain TA98 in the absence of S9 mix. In addition, an HPLC‐Ames histogram showed that peaks of mutagenicity corresponding to 1‐NP and diNPs accounted for 75.7% (1‐NP, 4.9%; 1,6‐diNP, 17.1%; 1,8‐diNP, 46.3%; 1,3‐diNP, 7.4%) of the HPLC‐recovered mutagenicity for strain TA98 without S9 mix. These results suggest that kerosene heaters, especially immediately after ignition, create mutagenic substances such as NPs. PMID:3128503
Mathematical Thinking and Creativity through Mathematical Problem Posing and Solving

ERIC Educational Resources Information Center

Ayllón, María F.; Gómez, Isabel A.; Ballesta-Claver, Julio

2016-01-01

This work shows the relationship between the development of mathematical thinking and creativity with mathematical problem posing and solving. Creativity and mathematics are disciplines that do not usually appear together. Both concepts constitute complex processes sharing elements, such as fluency (number of ideas), flexibility (range of ideas),…
Problem Posing Based on Investigation Activities by University Students

ERIC Educational Resources Information Center

da Ponte, Joao Pedro; Henriques, Ana

2013-01-01

This paper reports a classroom-based study involving investigation activities in a university numerical analysis course. The study aims to analyse students' mathematical processes and to understand how these activities provide opportunities for problem posing. The investigations were intended to stimulate students in asking questions, to trigger…
Examining Mathematics Classroom Interactions: Elevating Student Roles in Teaching and Learning

ERIC Educational Resources Information Center

Kent, Laura

2017-01-01

This article introduces a model entitled, "Responsive Teaching through Problem Posing" or RTPP, that addresses a type of reform oriented mathematics teaching based on posing relevant problems, positioning students as experts of mathematics, and facilitating discourse. RTPP incorporates decades of research on students' thinking in…
Mutagenicity of diesel exhaust particles and oil shale particles dispersed in lecithin surfactant.

PubMed

Wallace, W E; Keane, M J; Hill, C A; Xu, J; Ong, T M

1987-01-01

Diesel exhaust particulate material from exhaust pipe scrapings of two trucks, diluted automobile diesel exhaust particulate material collected on filters, and two oil shale ores were prepared for the Ames mutagenicity assay by dichloromethane (DCM) extraction, by dispersion into 0.85% saline, or by dispersion into dipalmitoyl lecithin (DPL) emulsion in saline. Salmonella typhimurium TA98 was used to detect frameshift mutagens in the samples. Samples of diesel soot gave positive mutagenic responses with both DCM extraction and DPL dispersion, with the DPL dispersion giving higher results in some cases. The results suggest that possible mutagens associated with inhaled particles may be dispersed or solubilized into the phospholipid component of pulmonary surfactant and become active in such a phase.
MUTAGENIC CHARACTERISTICS OF RIVER WATERS FLOWING THROUGH LARGE METROPOLITAN AREAS IN NORTH AMERICA

EPA Science Inventory

Mutagenic characteristics of river waters flowing through large metropolitan areas in North America

The hanging technique using blue rayon, which specifically adsorbs mutagens with multicyclic planar structures, has the advantages over most conventional methods of not havi...
Is Tobacco Smoke a Germ-Cell Mutagen?

EPA Science Inventory

Although no international organization exists to declare whether an agent is a germ-cell mutagen, tobacco smoke may be a human germ-cell mutagen. In the mouse, tobacco smoke induces a significant increase in the mutation frequency at an expanded simple tandem repeat (ESTR) locus....
TOPICAL REVIEW: MUTAGENICITY AND CARCINOGENICITY OF AIR

EPA Science Inventory

Although both outdoor and indoor airs provide exposure to mutagens and carcinogens, this review shows that the level of hazard is highly variable. Outdoor air was first shown to be carcinogenic in 1942 and mutagenic in 1975; and studies examining the genotoxicity of indoor air so...
Effects of diet composition on mutagenic activity in urine.

PubMed

Ohara, Akihiro; Matsuhisa, Tsugio

2004-01-01

The effects of dietary habits on mutagenic activity in urine were investigated using the umu test based on the use of the genetically engineered bacteria Salmonella typhimurium TA 1535 pSK1002. Genotoxic effects in sample urine were detected by measuring the activation of the SOS response in the bacteria and recording the beta- galactosidase activity. Human subjects consisted of smokers and non-smokers. Urine from subjects who consumed fish showed the highest mutagenic activity, followed by the urine samples from subjects who ate pork or beef. Chicken induced a low level of mutagenic activity. When the subjects ate fried or roasted animal foods, the urine samples gave higher mutagenicity than the urine samples from the subject who consumed non-fried or non-roasted animal foods. When the subject ate vegetables along with a diet rich in animal foods, the activity in urine decreased. Herbs and spices gave the same tendency toward decline as vegetables. Non-smoker urine shower mutagenic activity than samples from smokers.
Mutagenicity of particulate emissions from the M16 rifle: variation with particle size.

PubMed

Palmer, W G; Andrews, A W; Mellini, D; Terra, J A; Hoffmann, F J; Hoke, S H

1994-08-01

Emissions generated by firing the M16 rifle with the propellant WC844 in a combustion chamber designed to simulate conditions of actual use were tested for mutagenic activity in the Salmonella/Ames assay. Dimethyl sulfoxide extracts of emissions collected from either the breech or muzzle end of the rifle were mutagenic in three strains of Salmonella (TA1537, TA1538, and TA98) both in the presence and absence of metabolic activation systems (S9). The extracts were negative in strains TA100 and TA102. Aerosols generated by firing the M16 rifle were fractionated according to aerodynamic diameter. Submicrometer particles were far more mutagenic than particles with aerodynamic diameters between 1 and 15 microns. The mutagens associated with the smaller particles were more active in the presence of S9, while extracts of larger particles were as active, or more active, in the absence of S9. Heavier particles, which settled rapidly out of the airstream, were not mutagenic.

Modulatory effects of Cassia fistula fruits against free radicals and genotoxicity of mutagens.

PubMed

Kaur, Sandeep; Kumar, Manish; Kaur, Paramjeet; Kaur, Varinder; Kaur, Satwinderjeet

2016-12-01

Cassia fistula L. (Fabaceae) fruits are highly recommended in folklore medicine for curing various ailments. In the current study, methanol (CaFM), hexane (CaFH), chloroform (CaFCl), ethyl acetate (CaFE), butanol (CaFB) and aqueous (CaFA) fractions of C. fistula fruits were investigated for their potential to inhibit the genotoxicity of mutagens and free radicals. The antimutagenicity of fractions was evaluated against the reactive carcinogenic ester generating mutagen, 2-aminofluorene (2-AF) and frame-shift mutation inducing mutagen, 4-nitro-o-phenylenediamine (NPD) in Ames Salmonella typhimurium TA98 tester strain. Among the fractions, CaFE showed strongest protective effect against the mutagenicity of both S9-dependent and direct-acting mutagen with an inhibitory percentage of 81% and 64% at the concentration of 1 × 10 3 and 2.5 × 10 3 respectively. All the fractions were analyzed for free radical scavenging activity using DPPH, nitric oxide, lipid peroxidation and superoxide anion assays. CaFE fraction showed maximum antioxidant activity in comparison to other fractions with an IC 50 of 97.01, 172.36, 144 and 264.79 μg/ml respectively. High performance liquid chromatography showed the presence of catechin, epicatechin and umbelliferone in appreciable amount which may account for its efficacy in combating free radicals and also showed protective effect against the mutagenicity of S9-dependent mutagen, 2-AF. Copyright Â© 2016 Elsevier Ltd. All rights reserved.
Mutation signatures of carcinogen exposure: genome-wide detection and new opportunities for cancer prevention

PubMed Central

2014-01-01

Exposure to environmental mutagens is an important cause of human cancer, and measures to reduce mutagenic and carcinogenic exposures have been highly successful at controlling cancer. Until recently, it has been possible to connect the chemical characteristics of mutagens to actual mutations observed in human tumors only indirectly. Now, next-generation sequencing technology enables us to observe in detail the DNA-sequence-level effects of well-known mutagens, such as ultraviolet radiation and tobacco smoke, as well as endogenous mutagenic processes, such as those involving activated DNA cytidine deaminases (APOBECs). We can also observe the effects of less well-known but potent mutagens, including those recently found to be present in some herbal remedies. Crucially, we can now tease apart the superimposed effects of several mutational exposures and processes and determine which ones occurred during the development of individual tumors. Here, we review advances in detecting these mutation signatures and discuss the implications for surveillance and prevention of cancer. The number of sequenced tumors from diverse cancer types and multiple geographic regions is growing explosively, and the genomes of these tumors will bear the signatures of even more diverse mutagenic exposures. Thus, we envision development of wide-ranging compendia of mutation signatures from tumors and a concerted effort to experimentally elucidate the signatures of a large number of mutagens. This information will be used to link signatures observed in tumors to the exposures responsible for them, which will offer unprecedented opportunities for prevention. PMID:25031618
Ways of Thinking Associated with Mathematics Teachers' Problem Posing in the Context of Division of Fractions

ERIC Educational Resources Information Center

Koichu, Boris; Harel, Guershon; Manaster, Alfred

2013-01-01

Twenty-four mathematics teachers were asked to think aloud when posing a word problem whose solution could be found by computing 4/5 divided by 2/3. The data consisted of verbal protocols along with the written notes made by the subjects. The qualitative analysis of the data was focused on identifying the structures of the problems produced and…
USE OF BIOASSAY-DIRECTED CHEMICAL ANALYSIS FOR IDENTIFYING MUTAGENIC COMPOUNDS IN URBAN AIR AND COMBUSTION EMISSIONS

EPA Science Inventory

Bioassay-directed chemical analysis fractionation has been used for 30 years to identify mutagenic classes of compounds in complex mixtures. Most studies have used the Salmonella (Ames) mutagenicity assay, and we have recently applied this methodology to two standard reference sa...
An Evaluation of the Mode of Action Framework for MutagenicCarcinogens Case Study II: Chromium (VI).

EPA Science Inventory

In response to the 2005 revised U.S Environmental Protection Agency’s (EPA) Cancer Guidelines, a strategy is being developed to include all mutagenicity and other genotoxicity data with any additional information to determine whether a carcinogen operates through a mutagenic mode...
40 CFR 799.9510 - TSCA bacterial reverse mutation test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the Salmonella/Mammalian-Microsome Mutagenicity Test. Mutation Research. 31, 347-364 (1975). (2) Maron, D.M. and Ames, B.N. Revised Methods for the Salmonella Mutagenicity Test. Mutation Research. 113... Bridges, B.A. Use of a Simplified Fluctuation Test to Detect Low Levels of Mutagens. Mutation Research. 38...
40 CFR 799.9510 - TSCA bacterial reverse mutation test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the Salmonella/Mammalian-Microsome Mutagenicity Test. Mutation Research. 31, 347-364 (1975). (2) Maron, D.M. and Ames, B.N. Revised Methods for the Salmonella Mutagenicity Test. Mutation Research. 113... Bridges, B.A. Use of a Simplified Fluctuation Test to Detect Low Levels of Mutagens. Mutation Research. 38...
40 CFR 799.9510 - TSCA bacterial reverse mutation test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the Salmonella/Mammalian-Microsome Mutagenicity Test. Mutation Research. 31, 347-364 (1975). (2) Maron, D.M. and Ames, B.N. Revised Methods for the Salmonella Mutagenicity Test. Mutation Research. 113... Bridges, B.A. Use of a Simplified Fluctuation Test to Detect Low Levels of Mutagens. Mutation Research. 38...
EFFECT OF THE DECHLORINATING AGENT, ASCORBIC ACID, ON THE MUTAGENICITY OF CHLORINATED WATER SAMPLES

EPA Science Inventory

XAD resin adsorption has been widely used to concentrate the organic compounds present in chlorinated drinking waters prior to mutagenicity testing. Previous work has shown that mutagenic artifcats can arise due to the reaction of residual chlorine with the resins. Althrough the ...
Analysis of mutagenic activity of biohazardous organics in Kanawha River sediments. Technical completion report

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, A.R.; Waldron, M.C.

1988-01-01

Residual chemical contamination of Kanawha River sediments may constitute a health hazard. Sediment cores have been analyzed using a coupled bioassay/chemical fractionation procedure. Both bacterial mutagenicity and sister chromatid exchange (SCE) analyses were conducted on sediment samples. Pocatalico River sediments extracts showed no response in either bacterial mutagenicity assay or SCE assay. Extracts from Armour Creek and the Kanawha River induced mutagenicities in the presence of S9 enzymes. The same extracts produced a significant increase in human chromosomal cross-over events.
Lack of mutagens in deep-fat-fried foods obtained at the retail level.

PubMed

Taylor, S L; Berg, C M; Shoptaugh, N H; Scott, V N

1982-04-01

The basic methylene chloride extract from 20 of 30 samples of foods fried in deep fat failed to elicit any mutagenic response that could be detected in the Salmonella typhimurium/mammalian microsome assay. The basic extracts of the remaining ten samples (all three chicken samples studied, two of the four potato-chip samples, one of four corn-chip samples, the sample of onion rings, two of six doughnuts, and one of three samples of french-fried potato) showed evidence of weak mutagenic activity. In these samples, amounts of the basic extract equivalent to 28.5-57 g of the original food sample were required to produce revertants at levels of 2.6-4.8 times the background level. Only two of the acidic methylene chloride extracts from the 30 samples exhibited mutagenic activity greater than 2.5 times the background reversion level, and in both cases (one corn-chip and one shrimp sample) the mutagenic response was quite weak. The basic extract of hamburgers fried in deep fat in a home-style fryer possessed higher levels of mutagenic activity (13 times the background reversion level). However, the mutagenic activity of deep-fried hamburgers is some four times lower than that of pan-fried hamburgers.
Mutagenic atmospheres resulting from the photooxidation of aromatic hydrocarbon and NOx mixtures

NASA Astrophysics Data System (ADS)

Riedel, Theran P.; DeMarini, David M.; Zavala, Jose; Warren, Sarah H.; Corse, Eric W.; Offenberg, John H.; Kleindienst, Tadeusz E.; Lewandowski, Michael

2018-04-01

Although many volatile organic compounds (VOCs) are regulated to limit air pollution and the consequent health effects, the photooxidation products generally are not. Thus, we examined the mutagenicity in Salmonella TA100 of photochemical atmospheres generated in a steady-state atmospheric simulation chamber by irradiating mixtures of single aromatic VOCs, NOx, and ammonium sulfate seed aerosol in air. The 10 VOCs examined were benzene; toluene; ethylbenzene; o-, m-, and p-xylene; 1,2,4- and 1,3,5-trimethylbenzene; m-cresol; and naphthalene. Salmonella were exposed at the air-agar interface to the generated atmospheres for 1, 2, 4, 8, or 16 h. Dark-control exposures produced non-mutagenic atmospheres, illustrating that the gas-phase precursor VOCs were not mutagenic at the concentrations tested. Under irradiation, all but m-cresol and naphthalene produced mutagenic atmospheres, with potencies ranging from 2.0 (p-xylene) to 11.4 (ethylbenzene) revertants m3 mgC-1 h-1. The mutagenicity was due exclusively to direct-acting late-generation products of the photooxidation reactions. Gas-phase chemical analysis showed that a number of oxidized organic chemical species enhanced during the irradiated exposure experiments correlated (r ≥ 0.81) with the mutagenic potencies of the atmospheres. Molecular formulas assigned to these species indicated that they likely contained peroxy acid, aldehyde, alcohol, and other functionalities.
Meanings Given to Algebraic Symbolism in Problem-Posing

ERIC Educational Resources Information Center

Cañadas, María C.; Molina, Marta; del Río, Aurora

2018-01-01

Some errors in the learning of algebra suggest that students might have difficulties giving meaning to algebraic symbolism. In this paper, we use problem posing to analyze the students' capacity to assign meaning to algebraic symbolism and the difficulties that students encounter in this process, depending on the characteristics of the algebraic…
Enhancing Students' Communication Skills through Problem Posing and Presentation

ERIC Educational Resources Information Center

Sugito; E. S., Sri Mulyani; Hartono; Supartono

2017-01-01

This study was to explore how enhance communication skill through problem posing and presentation method. The subjects of this research were the seven grade students Junior High School, including 20 male and 14 female. This research was conducted in two cycles and each cycle consisted of four steps, they were: planning, action, observation, and…
Image-based aircraft pose estimation: a comparison of simulations and real-world data

NASA Astrophysics Data System (ADS)

Breuers, Marcel G. J.; de Reus, Nico

2001-10-01

The problem of estimating aircraft pose information from mono-ocular image data is considered using a Fourier descriptor based algorithm. The dependence of pose estimation accuracy on image resolution and aspect angle is investigated through simulations using sets of synthetic aircraft images. Further evaluation shows that god pose estimation accuracy can be obtained in real world image sequences.
Potential of goat probiotic to bind mutagens.

PubMed

Apás, Ana Lidia; González, Silvia Nelina; Arena, Mario Eduardo

2014-08-01

The mutagen binding ability of the goat probiotics (Lactobacillus reuteri DDL 19, Lactobacillus alimentarius DDL 48, Enterococcus faecium DDE 39, and Bifidobacterium bifidum DDBA) was evaluated. The oral administration of these probiotics reduced fecal mutagens and intestinal cancer markers in goats. Secondly, the effects of probiotics against the mutagenesis induced by sodium azide (SA), and Benzopyrene (B[α]P) by performing the modified Ames test using Salmonella typhimurium TA 100 was investigated. The capacity to bind benzopyrene and the stability of the bacterial-mutagen complex was analyzed by HPLC. The dismutagenic potential against both mutagens was proportional to probiotic concentration. Results showed that probiotic antimutagenic capacity against SA was ranging from 13 to 78%. The mixture of four goat probiotics (MGP) displayed higher antimutagenic activity against SA than any individual strains at the same cell concentration. This study shows that the highest diminution of mutagenicity in presence of B[α]P (74%) was observed in presence of MGP. The antimutagenic activity of nearly all the individual probiotic and the MGP were in concordance with the B[α]P binding determined by HPLC. According to our results, the B[α]P binding to probiotic was irreversible still after being washed with DMSO solution. The stability of the toxic compounds-bacterial cell binding is a key consideration when probiotic antimutagenic property is evaluated. MGP exhibits the ability to bind and detoxify potent mutagens, and this property can be useful in supplemented foods for goats since it can lead to the removal of potent mutagens and protect and enhance ruminal health and hence food safety of consumers. Copyright © 2014 Elsevier Ltd. All rights reserved.
Development of fecal microbial enzyme mix for mutagenicity assay of natural products.

PubMed

Yeo, Hee Kyung; Hyun, Yang-Jin; Jang, Se-Eun; Han, Myung Joo; Lee, Yong Sup; Kim, Dong-Hyun

2012-06-01

Orally administered herbal glycosides are metabolized to their hydrophobic compounds by intestinal microflora in the intestine of animals and human, not liver enzymes, and absorbed from the intestine to the blood. Of these metabolites, some, such as quercetin and kaempherol, are mutagenic. The fecal bacterial enzyme fraction (fecalase) of human or animals has been used for measuring the mutagenicity of dietary glycosides. However, the fecalase activity between individuals is significantly different and its preparation is laborious and odious. Therefore, we developed a fecal microbial enzyme mix (FM) usable in the Ames test to remediate the fluctuated reaction system activating natural glycosides to mutagens. We selected, cultured, and mixed 4 bacteria highly producing glycosidase activities based on a cell-free extract of feces (fecalase) from 100 healthy Korean volunteers. When the mutagenicities of rutin and methanol extract of the flos of Sophora japonica L. (SFME), of which the major constituent is rutin, towards Salmonella typhimurium strains TA 98, 100, 102, 1,535, and 1,537 were tested using FM and/or S9 mix, these agents were potently mutagenic. These mutagenicities using FM were not significantly different compared with those using Korean fecalase. SFME and rutin were potently mutagenic in the test when these were treated with fecalase or FM in the presence of S9 mix, followed by those treated with S9 mix alone and those with fecalase or FM. Freeze-dried FM was more stable in storage than fecalase. Based on these findings, FM could be usable instead of human fecalase in the Ames test.
Assessment of the Microscreen phage-induction assay for screening hazardous wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houk, V.S.; DeMarini, D.M.

1987-09-01

The Microscreen phage-induction assay, which quantitatively measures the induction of prophage lambda in Escherichia coli WP2s(lambda), was used to test 14 crude (unfractionated) hazardous industrial waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 picograms per ml. Comparisons between the mutagenicity of these waste samples in Salmonella and their ability to induce prophage lambda indicate that the Microscreen phage-induction assay detected genotoxic activity in all but one of the wastes that were mutagenic in Salmonella. Moreover, the Microscreen assaymore » detected as genotoxic 5 additional wastes that were not detected in the Salmonella assay. The applicability of the Microscreen phage-induction assay for screening hazardous wastes for genotoxic activity is discussed along with some of the problems associated with screening highly toxic wastes containing toxic volatile compounds.« less
Use of the microscreen phage-induction assay to assess the genotoxicity of 14 hazardous industrial wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houk, V.S.; DeMarini, D.M.

1988-01-01

The Microscreen phage-induction assay, which quantitatively measures the induction of prophage lambda in Escherichia coli WP2s(lambda), was used to test 14 crude (unfractionated) hazardous industrial waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 pg per ml. Comparisons between the ability of these waste samples to induce prophage and their mutagenicity in the Salmonella reverse mutation assay indicate that the phage-induction assay detected genotoxic activity in all but one of the wastes that were mutagenic in Salmonella. Moreover, themore » Microscreen assay detected as genotoxic five additional wastes that were not detected in the Salmonella assay. The applicability of the Microscreen phage-induction assay for screening hazardous wastes for genotoxic activity is discussed, as are some of the problems associated with screening highly toxic wastes containing toxic volatile compounds.« less
Use of the Microscreen phage-induction assay to assess the genotoxicity of 14 hazardous industrial wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houk, V.S.; DeMarini, D.M.

1988-01-01

The Microscreen phage-induction assay, which quantitatively measures the induction of prophage lambda in Escherichia coli WP2s lambda, was used to test 14 crude (unfractionated) hazardous industrial-waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 picograms per ml. Comparisons between the mutagenicity of these waste samples in Salmonella and their ability to induce prophage lambda indicate that the Microscreen phage-induction assay detected genotoxic activity in all but one of the wastes that were mutagenic in Salmonella. Moreover, the Microscreen assaymore » detected as genotoxic 5 additional wastes that were not detected in the Salmonella assay. The applicability of the Microscreen phage-induction assay for screening hazardous wastes for genotoxic activity is discussed along with some of the problems associated with screening highly toxic wastes containing toxic volatile compounds.« less

THE CASE FOR THE CONTRIBUTION OF CRISTAIS RIVER NITRO-AMINOBENZENE DYES TO THE MUTAGENICITY OF AMBIENT SAMPLES

EPA Science Inventory

In order to verify if dyestuffs within an effluent of a textile industry was contributing to the systematic mutagenicity detected in the Cristais River, within the metropolitan region of Sao Paulo, mutagenic samples of the industrial effluent, crude water, and treated silt of the...
40 CFR 799.9510 - TSCA bacterial reverse mutation test.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Mutagenicity Test. Mutation Research. 31, 347-364 (1975). (2) Maron, D.M. and Ames, B.N. Revised Methods for the Salmonella Mutagenicity Test. Mutation Research. 113, 173-215 (1983). (3) Gatehouse, D., Haworth... Fluctuation Test to Detect Low Levels of Mutagens. Mutation Research. 38, 33-42 (1976). (10) Hubbard, S.A...
ASCORBIC ACID REDUCTION OF ACTIVE CHLORINE PRIOR TO DETERMINING AMES MUTAGENICITY OF CHLORINATED NATURAL ORGANIC MATTER (NOM)

EPA Science Inventory

Many potable water disinfection byproducts (DBPs) that result from the reaction of natural organic matter (NOM) with oxidizing chlorine are known or suspected to be carcinogenic and mutagenic. The Ames assay is routinely used to assess an overall level of mutagenicity for all com...
COMPARATIVE MUTAGENICITY OF HALOMETHANES AND HALONITROMETHANES IN SALMONELLA TA100: STRUCTURE-ACTIVITY ANALYSIS AND MUTATION SPECTRA. (ERD)

EPA Science Inventory

Halonitromethanes (HNMs) are a recently identified class of disinfection by-products (DPBs) in drinking water that are mutagenic in Salmonella and potent inducers of DNA strand breaks in mammalian cells. Here we compared the mutagenic potencies of the HNMs to those of their halo...
COMPARATIVE MUTAGENICITY OF HALOMETHANES AND HALONITROMETHANES IN SALMONELLA TA100: STRUCTURE-ACTIVITY ANALYSIS AND MUTATION SPECTRA

EPA Science Inventory

Halonitromethanes (HNMs) are a recently identified class of disinfection by-products (DPBs) in drinking water that are mutagenic in Salmonella and potent inducers of DNA strand breaks in mammalian cells. Here we compared the mutagenic potencies of the HNMs to those of their halom...
Effective Strategies for Monitoring and Regulating Chemical Mixtures and Contaminants Sharing Pathways of Toxicity

PubMed Central

Venkatesan, Arjun K.; Halden, Rolf U.

2015-01-01

Traditionally, hazardous chemicals have been regulated in the U.S. on a one-by-one basis, an approach that is slow, expensive and can be inefficient, as illustrated by a decades-long succession of replacing one type of organohalogen flame retardants (OHFRs) with another one, without addressing the root cause of toxicity and associated public health threats posed. The present article expounds on the need for efficient monitoring strategies and pragmatic steps in reducing environmental pollution and adverse human health impacts. A promising approach is to combine specific bioassays with state-of-the-art chemical screening to identify chemicals and chemical mixtures sharing specific modes of action (MOAs) and pathways of toxicity (PoTs). This approach could be used to identify and regulate hazardous chemicals as classes or compound families, featuring similar biological end-points, such as endocrine disruption and mutagenicity. Opportunities and potential obstacles of implementing this approach are discussed. PMID:26343697
Recent progress on biomass co-pyrolysis conversion into high-quality bio-oil.

PubMed

Hassan, H; Lim, J K; Hameed, B H

2016-12-01

Co-pyrolysis of biomass with abundantly available materials could be an economical method for production of bio-fuels. However, elimination of oxygenated compounds poses a considerable challenge. Catalytic co-pyrolysis is another potential technique for upgrading bio-oils for application as liquid fuels in standard engines. This technique promotes the production of high-quality bio-oil through acid catalyzed reduction of oxygenated compounds and mutagenic polyaromatic hydrocarbons. This work aims to review and summarize research progress on co-pyrolysis and catalytic co-pyrolysis, as well as their benefits on enhancement of bio-oils derived from biomass. This review focuses on the potential of plastic wastes and coal materials as co-feed in co-pyrolysis to produce valuable liquid fuel. This paper also proposes future directions for using this technique to obtain high yields of bio-oils. Copyright © 2016 Elsevier Ltd. All rights reserved.
Excretion of 3-hydroxy-benzo(a)pyrene and mutagenicity in rat urine after exposure to benzo(a)pyrene.

PubMed

Jongeneelen, F J; Leijdekkers, C M; Bos, R P; Theuws, J L; Henderson, P T

1985-10-01

3-hydroxy-benzo(a)pyrene (3-OH-B(a)P) and mutagenic activity in rat urine were determined after the oral administration of benzo(a)pyrene given in three repeated doses of 10, 20 and 50 mumol kg-1. The procedure for the determination of 3-OH-B(a)P consisted of enzymic hydrolysis, separation and HPLC-analysis. The mutagenic activity of concentrated urine samples was assayed with the Salmonella typhimurium strain TA98 in the presence of S9 mix and beta-glucuronidase. The urinary excretion of 3-OH-B(a)P and mutagens showed a correlation and both increased dose-dependently during the sampling period of 6 days. Data indicated that 3-OH-B(a)P can be regarded as a reliable representative of all urinary (pre)-mutagens derived from benzo(a)pyrene and exposure of rats to benzo(a)pyrene could be detected with greater sensitivity by the HPLC assay of 3-OH-B(a)P than with the non-specific mutagenicity assay.
Mutagenic Activity of Indigofera truxillensis and I. suffruticosa Aerial Parts

PubMed Central

Calvo, Tamara Regina; Cardoso, Cássia Regina Primila; da Silva Moura, Adriana Candido; dos Santos, Lourdes Campaner; Colus, Ilce Mara Syllos; Vilegas, Wagner; Varanda, Eliana Aparecida

2011-01-01

Indigofera truxillensis and I. suffruticosa, are used as a source of indigo dye and to treat several diseases. The mutagenic activity of the methanolic extracts from aerial parts, glycerolipid, flavonoid and alkaloid fractions of the extract were evaluated by means of Salmonella/microsome assays using TA100, TA98, TA102 and TA97a strains. The methanolic extract of I. truxillensis showed mutagenic activity in the TA98 strain without S9 while glycerolipid fraction was devoid of activity. The flavonoid and alkaloid fractions of both plants showed mutagenicity. Chemical analysis of flavonoid fractions of I. truxillensis and I. suffruticosa resulted in the identification of kaempferol, quercetin and their derivatives. The alkaloid fraction of both the species contained indigo and indirubin and indigo was found mainly responsible for the mutagenic activity. PMID:19696193
Influence of fuel properties, nitrogen oxides, and exhaust treatment by an oxidation catalytic converter on the mutagenicity of diesel engine emissions.

PubMed

Bünger, Jürgen; Krahl, Jürgen; Weigel, Andreas; Schröder, Olaf; Brüning, Thomas; Müller, Michael; Hallier, Ernst; Westphal, Götz

2006-08-01

Particle emissions of diesel engines (DEP) content polycyclic aromatic hydrocarbons (PAH) these compounds cause a strong mutagenicity of solvent extracts of DEP. We investigated the influence of fuel properties, nitrogen oxides (NO( x )), and an oxidation catalytic converter (OCC) on the mutagenic effects of DEP. The engine was fuelled with common diesel fuel (DF), low-sulphur diesel fuel (LSDF), rapeseed oil methyl ester (RME), and soybean oil methyl ester (SME) and run at five different load modes in two series with and without installation of an OCC in the exhaust pipe. Particles from the cooled and diluted exhaust were sampled onto glass fibre filters and extracted with dichloromethane in a soxhlet apparatus. The mutagenicity of the extracts was tested using the Salmonella typhimurium/mammalian microsome assay with tester strains TA98 and TA100. Without OCC the number of revertant colonies was lower in extracts of LSDF than in extracts of DF. The lowest numbers of revertant colonies were induced by the plant oil derived fuels. In three load modes, operation with the OCC led to a reduction of the mutagenicity. However, direct mutagenic effects under heavy duty conditions (load mode A) were significantly increased for RME (TA98, TA100) and SME (TA98). A consistent but not significant increase in direct mutagenicity was observed for DF and LSDF at load mode A, and for DF at idling (load mode E) when emissions were treated with the OCC. These results raise concern over the use of oxidation catalytic converters with diesel engines. We hypothesise that the OCC increases formation of direct acting mutagens under certain conditions by the reaction of NO( x ) with PAH resulting in the formation of nitrated-PAH. Most of these compounds are powerful direct acting mutagens.
Long-range transport of mutagens and other air pollutants from mainland East Asia to western Japan.

PubMed

Coulibaly, Souleymane; Minami, Hiroki; Abe, Maho; Hasei, Tomohiro; Oro, Tadashi; Funasaka, Kunihiro; Asakawa, Daichi; Watanabe, Masanari; Honda, Naoko; Wakabayashi, Keiji; Watanabe, Tetsushi

2015-01-01

Asian dust events, transport of dust particles from arid and semi-arid areas in China and Mongolia to the east by prevailing westerlies, are often observed in Japan in spring. In recent decades, consumption of fossil fuels has markedly increased in mainland East Asia with rapid economic growth, and severe air pollution has occurred. A part of air pollutants including mutagens, such as polycyclic aromatic hydrocarbons (PAHs), generated in mainland East Asia are thought to be transported to Japan by the prevailing westerlies, like Asian dust, and winter monsoon. The objective of this study was to clarify the long-range transport of mutagens and other air pollutants in East Asia. Thus, we collected total suspended particles (TSP) at a rural town in western Japan, namely, Yurihama in Tottori Prefecture, for 1 year (June 2012-May 2013), and investigated their chemical constituents and mutagenicity. Many TSP collected from January to March showed high mutagenicity toward Salmonella typhimurium YG1024 with and without S9 mix, and high levels of lead (Pb) and sulfate ions (SO4 (2-)), which are indicators of transboundary air pollutions from mainland East Asia, were detected in those TSP. A large amount of iron, which is an indicator of sand, was found in highly mutagenic TSP collected in March, but not in TSP collected in January and February. High levels of PAHs were detected in highly mutagenic TSP collected from January to March. The ratios of the concentration of fluoranthene to those of fluoranthene and pyrene suggested that the main source of PAHs in TSP collected in winter and spring was coal and biomass combustion. Backward trajectories of air masses on days when high levels of mutagenicity were found indicated that these air masses had traveled from eastern or northern China to Yurihama. These results suggest that high levels of mutagens were transported from mainland East Asia to western Japan, and this transportation accompanied Asian dust in March, but not in January and February.
Mutagenic activities of a chlorination by-product of butamifos, its structural isomer, and their related compounds.

PubMed

Kamoshita, Masahiro; Kosaka, Koji; Endo, Osamu; Asami, Mari; Aizawa, Takako

2010-01-01

The mutagenic activities of 5-methyl-2-nitrophenol (5M2NP), a chlorination by-product of butamifos, its structural isomer 2-methyl-5-nitrophenol (2M5NP), and related compounds were evaluated by the Ames assay. The mutagenic activities of 5M2NP and 2M5NP were negative or not particularly high. However, those of their chlorinated derivatives were increased in Salmonella typhimurium strain TA100 and the overproducer strains YG1026, and YG1029 in the absence and/or presence of a rat liver metabolic activation system (S9 mix), particularly for YG1029. The mutagenic activities of 6-chloro-2-methyl-5-nitrophenol (6C2M5NP) in YG1029 in the absence and presence of S9 mix were 70000 and 110000 revertants mg(-1), respectively. When nitro functions of 6C2M5NP and 4-chloro-5-methyl-2-nitrophenol (4C5M2NP) were reduced to amino functions, their mutagenic activities were markedly decreased. The mutagenic activities of 5M2NP and 4C5M2NP were lower than those of 2M5NP and 6C2M5NP, respectively. Thus, it was shown that substituent position is a key factor for the mutagenic activities of methylnitrophenols (MNPs) and related compounds. The mutagenic activities of the extracts of 2M5NP in chlorination increased early during the reaction time and then decreased. The main chlorination by-product contributing to the mutagenic activities of the extracts of 2M5NP in chlorination was 6C2M5NP. The results of chlorination of 2M5NP suggested that MNPs were present as their dichlorinated derivatives or further chlorination by-products in drinking water. Copyright 2009 Elsevier Ltd. All rights reserved.
Viewpoint Invariant Gesture Recognition and 3D Hand Pose Estimation Using RGB-D

ERIC Educational Resources Information Center

Doliotis, Paul

2013-01-01

The broad application domain of the work presented in this thesis is pattern classification with a focus on gesture recognition and 3D hand pose estimation. One of the main contributions of the proposed thesis is a novel method for 3D hand pose estimation using RGB-D. Hand pose estimation is formulated as a database retrieval problem. The proposed…
[Smoked sausages and food additives: evaluation of total mutagenic activity].

PubMed

Dugan, A M; Tkacheva, D L

2011-01-01

The paper deals with the evaluation of the total mutagenic activity of samples of the inorganic and organic fractions of three technology smoked sausages (boiled-smoked, semi-smoked, and raw-smoked) and some food additives used to manufacture the above sausages. Their mild and moderate mutagenic effects were recorded in a Salmonella typhimurium bacterial test system with a metabolic activation system. Physicochemical analysis of the fractions of the smoked sausages has shown that their study samples are substantially contaminated with heavy metals and representatives of polycyclic aromatic hydrocarbons, partially causing the mutagenic effects observed.
A method for the detection of protein-bound mutagens in food.

PubMed

Ibe, F I; Blowers, S D; Anderson, D; Massey, R

1994-01-01

To investigate the possible presence of protein-bound mutagens in food an analytical procedure has been devised in which the sample is enzymically hydrolysed, fractionated by HPLC and examined by a modified liquid incubation Ames assay. To validate the method MeIQx was added, as a model compound, to beefburger and a recovery of 82% obtained. The limit of detection for protein-bound mutagens was 1 microgram/kg, expressed as equivalents of MeIQx. No detectable mutagenicity was observed when the procedure was applied to samples of well cooked beefburger, irradiated chicken or mycoprotein.
In vitro and in vivo genotoxicity assessment of the dopamine receptor antagonist molindone hydrochloride.

PubMed

Krishna, Gopala; Gopalakrishnan, Gopa; Goel, Saryu

2016-05-01

Molindone hydrochloride is a dihydroindolone neuroleptic with dopamine D2 and D5 receptor antagonist activity. As an integral component of its preclinical safety evaluation, molindone hydrochloride was evaluated in a series of in vitro and in vivo genetic toxicology assays. In the bacterial reverse gene mutation assays employing four Salmonella tester strains (TA98, TA100, TA1535, and TA1537) and the E. coli tester strain WP2uvrA, molindone hydrochloride was negative in all strains, except TA100, in which it induced a positive response (up to 3-fold) in the presence of rat liver S9. With human S9, a small (2-fold), but nonreproducible, increase in revertants was observed in TA100 at the highest concentration of molindone tested (5,000 µg/plate). The mutagenicity was completely abrogated by the addition of glutathione and UDP-glucuronic acid to rat liver S9, suggesting detoxification of the mutagenic metabolite(s) by Phase II conjugation reactions, pathways commonly operational in humans. Molindone hydrochloride did not induce chromosomal aberrations in human lymphocyte cultures, did not elicit a positive response in a rat bone marrow micronucleus test for clastogencity/aneugenicity, and did not give a positive response in the rat liver comet assay for DNA damage. Collectively, the weight of evidence from these studies, combined with a large margin of safety and efficient detoxification through Phase II conjugation supports the interpretation that molindone hydrochloride does not pose a genotoxic risk to humans at the anticipated clinical dose levels. © 2016 Wiley Periodicals, Inc.
Reduced repair capacity of a DNA clustered damage site comprised of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 2-deoxyribonolactone results in an increased mutagenic potential of these lesions

DOE PAGES

Cunniffe, Siobhan; O’Neill, Peter; Greenberg, Marc M.; ...

2014-04-01

A signature of ionizing radiation is the induction of DNA clustered damaged sites. Non-double strand break (DSB) clustered damage has been shown to compromise the base excision repair pathway, extending the lifetimes of the lesions within the cluster, compared to isolated lesions. This increases the likelihood the lesions persist to replication and thus increasing the mutagenic potential of the lesions within the cluster. Lesions formed by ionizing radiation include 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and 2-deoxyribonolactone (dL). dL poses an additional challenge to the cell as it is not repaired by the short-patch base excision repair pathway. Here we show recalcitrant dL repairmore » is reflected in mutations observed when DNA containing it and a proximal 8-oxodGuo is replicated in Escherichia coli. 8-oxodGuo in close proximity to dL on the opposing DNA strand results in an enhanced frequency of mutation of the lesions within the cluster and a 20 base sequence flanking the clustered damage site in an E. coli based plasmid assay. In vitro repair of a dL lesion is reduced when compared to the repair of an abasic (AP) site and a tetrahydrofuran (THF), and this is due mainly to a reduction in the activity of polymerase β, leading to retarded FEN1 and ligase 1 activities. This study has given insights in to the biological effects of clusters containing dL.« less
Development of a Mobile Learning System Based on a Collaborative Problem-Posing Strategy

ERIC Educational Resources Information Center

Sung, Han-Yu; Hwang, Gwo-Jen; Chang, Ya-Chi

2016-01-01

In this study, a problem-posing strategy is proposed for supporting collaborative mobile learning activities. Accordingly, a mobile learning environment has been developed, and an experiment on a local culture course has been conducted to evaluate the effectiveness of the proposed approach. Three classes of an elementary school in southern Taiwan…
An Investigation of Pattern Problems Posed by Middle School Mathematics Preservice Teachers Using Multiple Representation

ERIC Educational Resources Information Center

Yilmaz, Yasemin; Durmus, Soner; Yaman, Hakan

2018-01-01

This study investigated the pattern problems posed by middle school mathematics preservice teachers using multiple representations to determine both their pattern knowledge levels and their abilities to transfer this knowledge to students. The design of the study is the survey method, one of the quantitative research methods. The study group was…
A Problem Posing-Based Practicing Strategy for Facilitating Students' Computer Programming Skills in the Team-Based Learning Mode

ERIC Educational Resources Information Center

Wang, Xiao-Ming; Hwang, Gwo-Jen

2017-01-01

Computer programming is a subject that requires problem-solving strategies and involves a great number of programming logic activities which pose challenges for learners. Therefore, providing learning support and guidance is important. Collaborative learning is widely believed to be an effective teaching approach; it can enhance learners' social…

Problem-Posing as a Didactic Resource in Formal Mathematics Courses to Train Future Secondary School Mathematics Teachers

ERIC Educational Resources Information Center

Solórzano, Lorena Salazar

2015-01-01

Beginning university training programs must focus on different competencies for mathematics teachers, i.e., not only on solving problems, but also on posing them and analyzing the mathematical activity. This paper reports the results of an exploratory study conducted with future secondary school mathematics teachers on the introduction of…
Mutagenic activity associated with by-products of drinking water disinfection by chlorine, chlorine dioxide, ozone and UV-irradiation.

PubMed Central

Zoeteman, B C; Hrubec, J; de Greef, E; Kool, H J

1982-01-01

A retrospective epidemiological study in The Netherlands showed a statistical association between chlorination by-products in drinking water and cancer of the esophagus and stomach for males. A pilot-plant study with alternative disinfectants was carried out with stored water of the Rivers Rhine and Meuse. It was demonstrated that the increase of direct acting mutagens after treatment with chlorine dioxide is similar to the effect of chlorination. Ozonation of Rhine water reduced the mutagenic activity for Salmonella typhimurium TA 98 both with and without metabolic activation. UV alone hardly affects the mutagenicity of the stored river water for S. typh. TA 98. In all studies, practically no mutagenic activity for S. typh. TA 100 was found. Although remarkable changes in the concentration of individual organic compounds are reported, the identity of the mutagens detected is yet unclear. Compounds of possible interest due to their removal by ozonation are 1,3,3-trimethyloxindole, dicyclopentadiene and several alkylquinolines. Compounds which might be responsible for the increased mutagenicity after chlorination are two brominated acetonitriles and tri(2-chlorethyl) phosphate. Furthermore, the concentration procedure with adsorption on XAD resin and the subsequent elution step may have affected the results. It is proposed to focus further research more on the less volatile by-products of disinfection than on the trihalomethanes. PMID:7151762
Mutagenicity of drinking water sampled from the Yangtze River and Hanshui River (Wuhan section) and correlations with water quality parameters.

PubMed

Lv, Xuemin; Lu, Yi; Yang, Xiaoming; Dong, Xiaorong; Ma, Kunpeng; Xiao, Sanhua; Wang, Yazhou; Tang, Fei

2015-03-31

A total of 54 water samples were collected during three different hydrologic periods (level period, wet period, and dry period) from Plant A and Plant B (a source for Yangtze River and Hanshui River water, respectively), and several water parameters, such as chemical oxygen demand (COD), turbidity, and total organic carbon (TOC), were simultaneously analyzed. The mutagenicity of the water samples was evaluated using the Ames test with Salmonella typhimurium strains TA98 and TA100. According to the results, the organic compounds in the water were largely frame-shift mutagens, as positive results were found for most of the tests using TA98. All of the finished water samples exhibited stronger mutagenicity than the relative raw and distribution water samples, with water samples collected from Plant B presenting stronger mutagenic strength than those from Plant A. The finished water samples from Plant A displayed a seasonal-dependent variation. Water parameters including COD (r = 0.599, P = 0.009), TOC (r = 0.681, P = 0.02), UV254 (r = 0.711, P = 0.001), and total nitrogen (r = 0.570, P = 0.014) exhibited good correlations with mutagenicity (TA98), at 2.0 L/plate, which bolsters the argument of the importance of using mutagenicity as a new parameter to assess the quality of drinking water.
Mutagenicity of drinking water sampled from the Yangtze River and Hanshui River (Wuhan section) and correlations with water quality parameters

PubMed Central

Lv, Xuemin; Lu, Yi; Yang, Xiaoming; Dong, Xiaorong; Ma, Kunpeng; Xiao, Sanhua; Wang, Yazhou; Tang, Fei

2015-01-01

A total of 54 water samples were collected during three different hydrologic periods (level period, wet period, and dry period) from Plant A and Plant B (a source for Yangtze River and Hanshui River water, respectively), and several water parameters, such as chemical oxygen demand (COD), turbidity, and total organic carbon (TOC), were simultaneously analyzed. The mutagenicity of the water samples was evaluated using the Ames test with Salmonella typhimurium strains TA98 and TA100. According to the results, the organic compounds in the water were largely frame-shift mutagens, as positive results were found for most of the tests using TA98. All of the finished water samples exhibited stronger mutagenicity than the relative raw and distribution water samples, with water samples collected from Plant B presenting stronger mutagenic strength than those from Plant A. The finished water samples from Plant A displayed a seasonal-dependent variation. Water parameters including COD (r = 0.599, P = 0.009), TOC (r = 0.681, P = 0.02), UV254 (r = 0.711, P = 0.001), and total nitrogen (r = 0.570, P = 0.014) exhibited good correlations with mutagenicity (TA98), at 2.0 L/plate, which bolsters the argument of the importance of using mutagenicity as a new parameter to assess the quality of drinking water. PMID:25825837
Mutagenicity assessment of aerosols in emissions from domestic combustion processes.

PubMed

Canha, Nuno; Lopes, Isabel; Vicente, Estela Domingos; Vicente, Ana M; Bandowe, Benjamin A Musa; Almeida, Susana Marta; Alves, Célia A

2016-06-01

Domestic biofuel combustion is one of the major sources of regional and local air pollution, mainly regarding particulate matter and organic compounds, during winter periods. Mutagenic and carcinogenic activity potentials of the ambient particulate matter have been associated with the fraction of polycyclic aromatic hydrocarbons (PAH) and their oxygenated (OPAH) and nitrogenated (NPAH) derivatives. This study aimed at assessing the mutagenicity potential of the fraction of this polycyclic aromatic compound in particles (PM10) from domestic combustion by using the Ames assays with Salmonella typhimurium TA98 and TA100. Seven biofuels, including four types of pellets and three agro-fuels (olive pit, almond shell and shell of pine nuts), were tested in an automatic pellet stove, and two types of wood (Pinus pinaster, maritime pine, and Eucalyptus globulus, eucalypt) were burned in a traditional wood stove. For this latter appliance, two combustion phases-devolatilisation and flaming/smouldering-were characterised separately. A direct-acting mutagenic effect for the devolatilisation phase of pine combustion and for both phases of eucalypt combustion was found. Almond shell revealed a weak direct-acting mutagenic effect, while one type of pellets, made of recycled wastes, and pine (devolatilisation) presented a cytotoxic effect towards strain TA100. Compared to the manually fired appliance, the automatic pellet stove promoted lower polyaromatic mutagenic emissions. For this device, only two of the studied biofuels presented a weak mutagenic or cytotoxic potential.
Mutagenic synergism detected between dimethyl sulfate and X-rays but not found between N-methyl-N-nitrosourea and X-rays in the stamen hairs of Tradescantia clone BNL 4430.

PubMed

Shima, N; Ichikawa, S

1995-09-01

Mutagenic interactions with X-rays of two monofunctional alkylating agents, dimethyl sulfate (DMS) and N-methyl-N-nitrosourea (MNU), were studied in the stamen hairs of Tradescantia clone BNL 4430, a blue/pink heterozygote. The young inflorescence-bearing shoots with roots cultivated in the nutrient solution circulating growth chamber were used as tester plants. Synergism between two different mutagens was judged to have occurred when the mutation frequency observed after applying the two mutagens concurrently was statistically significantly higher than the mutation frequency expected from the additive effects of the two mutagens. Clear synergistic effects in inducing somatic pink mutations were detected with all combinations of doses of DMS and X-rays examined, even in a relatively low X-ray dose range (down to 299 mGy), resembling those confirmed earlier between ethyl methanesulfonate (EMS) and X-rays, but somewhat differing from the synergisms observed earlier between methyl methanesulfonate (MMS) and X-rays. On the other hand, no mutagenic synergism was detected between MNU and X-rays, even in a relatively high X-ray dose range (up to 862 mGy). The presence or absence of mutagenic synergisms of these alkylating agents with X-rays could be related to the action mechanism of each alkylating agent.
Mutagenicity and antimutagenicity of extracts of three spices and a medicinal plant in Thailand.

PubMed

Higashimoto, M; Purintrapiban, J; Kataoka, K; Kinouchi, T; Vinitketkumnuen, U; Akimoto, S; Matsumoto, H; Ohnishi, Y

1993-11-01

Three kinds of spices (caraway, coriander and black pepper seeds) and a medicinal plant called 'tong tak' in Thai (Baliospermum axillar, a species of the spurge family) were fractionated into hot water, methanol and hexane extracts. These extracts were not mutagenic for Salmonella typhimurium strains TA98 and TA100 by the Ames assay. However, when the extracts were treated with nitrite, samples of the water and methanol extracts were mutagenic for strain TA100 without metabolic activation. The mutagenicity of the nitrite-treated methanol and hot water extracts of black pepper was highest (8380 and 22,200 His+ per 0.1 g of spice powder, respectively), and that of the nitrite-treated hot water extracts of caraway and tong tak was moderate. The hot water extracts were examined for their antimutagenic activity against mutagenicity induced by various carcinogens by the Ames assay, using the preincubation technique. The tested samples (equivalent to 1-2 mg of spice powder) reduced the mutagenicity induced by 2.7 nmole (397 ng) of N-methyl-N'-nitro-N-nitrosoguanidine by more than 84%, and that induced by dimethylnitrosamine (1.48 mg) or ICR-170 (10 ng) by 30-60%. However, they did not inhibit the mutagenic activity of 1-nitropyrene, 3-nitrofluoranthene, AF-2, methyl methanesulfonate, N-ethyl-N'-nitro-N-nitrosoguanidine, 2-aminoanthracene, 2-acetylaminofluorene, benzo[a]pyrene or IQ.
Assessment of the mutagenic potential of cyanobacterial extracts and pure cyanotoxins.

PubMed

Sieroslawska, Anna

2013-11-01

The aim of the study was to assess the mutagenic potential of extracts obtained from the cyanobacterial bloom-forming cells harvested from the water body located in Lubelszczyzna region of southeastern Poland. Three cyanotoxins, microcystin-LR, cylindrospermopsin and anatoxin-a were detected in some of the studied samples in different concentrations. All extracts were assessed for their potential mutagenic effects with the use of a short-term bacterial assay, the Ames test. Mutagenic activity was observed in four of all ten studied extracts, mainly toward the Salmonella typhimurium TA100 strain. On the contrary, the cyanotoxins in purified forms occurred not to be mutagenic or cytotoxic towards S. typhimurium TA98, TA100, TA1535, TA1537 and Escherichia coli WP2 uvrA and WP2 [pKM101] up to a concentration of 10 μg/ml. Similarly, there were no effects after bacteria exposure to the mixture of purified toxins. It has been also detected that after fractionation, genotoxic impact of previously mutagenic extracts was weaker and the highest potency in revertant induction possessed fractions containing very hydrophilic compounds. The results indicate, that while tested cyanotoxins were not directly responsible for the observed mutagenicity of the extracts analysed, some synergistic interactions with other unidentified cyanobacterial-derived factors involved in the process are possible. Copyright © 2013 Elsevier Ltd. All rights reserved.
Mutagenicity of commercial hair dyes and detection of 2,7-diaminophenazine.

PubMed

Watanabe, T; Hirayama, T; Fukui, S

1990-08-01

Four commercial oxidative-type hair dye formulations, A, B, C, and D, were treated with hydrogen peroxide (H2O2) to simulate normal conditions of use, and the oxidized hair dyes were tested for their mutagenicity in Salmonella typhimurium TA98 in the presence of a mammalian metabolic activation system (S9 mix). Most of them did not show obvious mutagenicity in the range of 1-25 microliters/plate and all exhibited bactericidal activity at 10 microliters/plate. In order to evaluate the mutagenicity of hair dyes both before and after H2O2 oxidation, rayon linked to a copper-phthalocyanine derivative (blue rayon) was used as an adsorbent for the elimination of interfering bactericidal compounds. Adsorbed compounds on blue rayon were eluted with ammoniacal methanol and eluents were subjected to the Ames test. The mutagenicity of the blue-rayon extracts in TA98 with S9 mix was increased by H2O2 oxidation. The blue-rayon extracts obtained from oxidized A and B were potent mutagens and reverted 334 and 999 colonies/10 microliters of original substance, respectively. In addition, 88 and 249 ng of 2,7-diaminophenazine, which was extremely mutagenic in TA98 with S9 mix, were detected in the extracts of 40 ml of the hair dye formulations A and B, respectively. The mutagenicity in oxidized hair dye formulations was successfully detected by use of blue-rayon extraction. 2,7-Diaminophenazine was only formed in the hair dye formulations containing m-phenylenediamine by H2O2 oxidation. Therefore, attention needs to be paid to the use of m-phenylenediamine as a hair dye component, not only for its own toxicity but also for that of its oxidation products.
Dietary Mutagen Exposure and Risk of Pancreatic Cancer

PubMed Central

Li, Donghui; Sue Day, Rena; Bondy, Melissa L.; Sinha, Rashmi; Nguyen, Nga T.; Evans, Douglas B.; Abbruzzese, James L.; Hassan, Manal M.

2007-01-01

To investigate the association between dietary exposure to food mutagens and risk of pancreatic cancer, we conducted a hospital-based case-control study at the University of Texas M. D. Anderson Cancer Center during June 2002 to May 2006. Atotal of 626 cases and 530 noncancer controls were frequency matched for race, sex and age (±5 years). Dietary exposure information was collected via personal interview using a meat preparation questionnaire. A significantly greater portion of the cases than controls showed a preference to well-done pork, bacon, grilled chicken, and pan-fried chicken, but not to hamburger and steak. Cases had a higher daily intake of food mutagens and mutagenicity activity (revertants per gram of daily meat intake) than controls did. The daily intakes of 2-amino-3,4,8-trimethylimidazo[4,5—f]quinoxaline (DiMeIQx) and benzo(a)pyrene (BaP), as well as the mutagenic activity, were significant predictors for pancreatic cancer (P = 0.008, 0.031, and 0.029, respectively) with adjustment of other confounders. A significant trend of elevated cancer risk with increasing DiMeIQx intake was observed in quintile analysis (Ptrend= 0.024). Ahigher intake of dietary mutagens (those in the two top quintiles) was associated with a 2-fold increased risk of pancreatic cancer among those without a family history of cancer but not among those with a family history of cancer. Apossible synergistic effect of dietary mutagen exposure and smoking was observed among individuals with the highest level of exposure (top 10%) to PhIP and BaP, Pinteraction= 0.09 and 0.099, respectively. These data support the hypothesis that dietary mutagen exposure alone and in interaction with other factors contribute to the development of pancreatic cancer. PMID:17416754
Dietary mutagen exposure and risk of pancreatic cancer.

PubMed

Li, Donghui; Day, Rena Sue; Bondy, Melissa L; Sinha, Rashmi; Nguyen, Nga T; Evans, Douglas B; Abbruzzese, James L; Hassan, Manal M

2007-04-01

To investigate the association between dietary exposure to food mutagens and risk of pancreatic cancer, we conducted a hospital-based case-control study at the University of Texas M. D. Anderson Cancer Center during June 2002 to May 2006. A total of 626 cases and 530 noncancer controls were frequency matched for race, sex and age (+/-5 years). Dietary exposure information was collected via personal interview using a meat preparation questionnaire. A significantly greater portion of the cases than controls showed a preference to well-done pork, bacon, grilled chicken, and pan-fried chicken, but not to hamburger and steak. Cases had a higher daily intake of food mutagens and mutagenicity activity (revertants per gram of daily meat intake) than controls did. The daily intakes of 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) and benzo(a)pyrene (BaP), as well as the mutagenic activity, were significant predictors for pancreatic cancer (P = 0.008, 0.031, and 0.029, respectively) with adjustment of other confounders. A significant trend of elevated cancer risk with increasing DiMeIQx intake was observed in quintile analysis (P(trend) = 0.024). A higher intake of dietary mutagens (those in the two top quintiles) was associated with a 2-fold increased risk of pancreatic cancer among those without a family history of cancer but not among those with a family history of cancer. A possible synergistic effect of dietary mutagen exposure and smoking was observed among individuals with the highest level of exposure (top 10%) to PhIP and BaP, P(interaction) = 0.09 and 0.099, respectively. These data support the hypothesis that dietary mutagen exposure alone and in interaction with other factors contribute to the development of pancreatic cancer.
Circular dichroism study of the interaction between mutagens and bilirubin bound to different binding sites of serum albumins

NASA Astrophysics Data System (ADS)

Orlov, Sergey; Goncharova, Iryna; Urbanová, Marie

Although recent investigations have shown that bilirubin not only has a negative role in the organism but also exhibits significant antimutagenic properties, the mechanisms of interactions between bilirubin and mutagens are not clear. In this study, interaction between bilirubin bound to different binding sites of mammalian serum albumins with structural analogues of the mutagens 2-aminofluorene, 2,7-diaminofluorene and mutagen 2,4,7-trinitrofluorenone were investigated by circular dichroism and absorption spectroscopy. Homological human and bovine serum albumins were used as chiral matrices, which preferentially bind different conformers of bilirubin in the primary binding sites and make it observable by circular dichroism. These molecular systems approximated a real system for the study of mutagens in blood serum. Differences between the interaction of bilirubin bound to primary and to secondary binding sites of serum albumins with mutagens were shown. For bilirubin bound to secondary binding sites with low affinity, partial displacement and the formation of self-associates were observed in all studied mutagens. The associates of bilirubin bound to primary binding sites of serum albumins are formed with 2-aminofluorene and 2,4,7-trinitrofluorenone. It was proposed that 2,7-diaminofluorene does not interact with bilirubin bound to primary sites of human and bovine serum albumins due to the spatial hindrance of the albumins binding domains. The spatial arrangement of the bilirubin bound to serum albumin along with the studied mutagens was modelled using ligand docking, which revealed a possibility of an arrangement of the both bilirubin and 2-aminofluorene and 2,4,7-trinitrofluorenone in the primary binding site of human serum albumin.
Rat liver endothelial and Kupffer cell-mediated mutagenicity and polycyclic aromatic hydrocarbons and aflatoxin B sub 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinberg, P.; Schlemper, B.; Molitor, E.

The ability of isolated rat liver endothelial and Kupffer cells to activate benzo(a)pyrene (BP), trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene (DDBP), trans-1,2-dihydroxy-1,2-dihydrochrysene (DDCH), and aflatoxin B{sub 1} (AFB{sub 1}) to mutagenic metabolites was assessed by means of a cell-mediated bacterial mutagenicity assay and compared with the ability of parenchymal cells to activate these compounds. Endothelial and Kupffer cells from untreated rats were able to activate AFB{sub 1} and DDBP; DDBP was activated even in the absence of an NADPH-generating system. Pretreating the animals with Aroclor 1254 strongly enhanced the mutagenicity of the dihydrodiol, whereas the mutagenicity of AFB{sub 1} showed a slight increase. BP andmore » DDCH were only activated by endothelial and Kupffer cells isolated from Aroclor 1254-pretreated rats. Parenchymal cells form untreated animals activated all four carcinogens tested; Aroclor 1254 enhanced the parenchymal cell-mediated mutagenicity of BP and DDCH but did not affect that of DDBP and clearly reduced that of AFB{sub 1}. The reduced mutagenicity of AFB{sub 1} correlates with the decrease in the amount of 2{alpha}-hydroxytestosterone formed when testosterone was incubated with parenchymal cell microsomes from Aroclor 1254-pretreated rats (compared with microsomes from untreated animals): the formation of 2{alpha}-hydroxytestosterone is specifically catalyzed by cytochrome P-450h, a hemoprotein thought to be involved in the activation of AFB{sub 1}. These results show that not only rat liver parenchymal cells, but also endothelial and Kupffer cells, activated several carcinogens to mutagenic metabolites.« less
Assimilating data into open ocean tidal models

NASA Astrophysics Data System (ADS)

Kivman, Gennady A.

The problem of deriving tidal fields from observations by reason of incompleteness and imperfectness of every data set practically available has an infinitely large number of allowable solutions fitting the data within measurement errors and hence can be treated as ill-posed. Therefore, interpolating the data always relies on some a priori assumptions concerning the tides, which provide a rule of sampling or, in other words, a regularization of the ill-posed problem. Data assimilation procedures used in large scale tide modeling are viewed in a common mathematical framework as such regularizations. It is shown that they all (basis functions expansion, parameter estimation, nudging, objective analysis, general inversion, and extended general inversion), including those (objective analysis and general inversion) originally formulated in stochastic terms, may be considered as utilizations of one of the three general methods suggested by the theory of ill-posed problems. The problem of grid refinement critical for inverse methods and nudging is discussed.
Mutagenicity of streptozotocin and several other nitrosourea compounds in Salmonella typhimurium.

PubMed

Zimmer, D M; Bhuyan, B K

1976-11-01

The following nitrosourea compounds were compared for their ability to induce mutation (to histidine independence) in the histidine-requiring auxotroph Salmonella typhimurium his G46: MNU, streptozotocin (SZ, streptozocin) and its analogs SZA1 and SZA2, and the antitumor drugs BCNU, CCNU and DCNU. At equitoxic doses SZ, SZA1, SZA2 and MNU were almost equally mutagenic causing 150, 42, 140 and 170 mutants/106 survivors at 20% lethal dose (ID20) ALTHOUGH, ON A WIEGHT BASIS, SZ was the most mutagenic of all the compounds tested. At ID20 BCNU, CCNU and DCNU gave about 0.5 mutants/106 survivors. Our results show that these nitrosoureas, in common with many other drugs (such as cyclophosphamide, daunomycin, etc.) used in cancer chemotherapy, are highly mutagenic. The implication of our results in the screening of drugs for their mutagenicity to man is discussed.
Optimization of the Ames/salmonella mutagenicity assay for use with extracts of aquatic sediments

USGS Publications Warehouse

Papoulias, Diana M.; Buckler, Denny R.; Tillitt, Donald E.

1996-01-01

Non-mutagenic components interfered with the ability of the standard Ames/salmonella assay to detect mutagenicity in extracts of contaminated Great Lakes sediments. The use of gel permeation chromatography (GPC) to remove these macromolecules from methylene chloride extracts prior to Ames testing enhanced the likelihood of transfer of mutagenic components into dimethyl sulf oxide (the assay solvent). Therefore, to optimize the assay's sensitivity we pre-treated sediment extracts using GPC and increased metabolic activity through the use of a 30% S9 mix. Increasing the level of Aroclor 1254-induced rat liver S9, typically used to metabolically activate promutagens, had the additional beneficial effect of reducing the cytotoxicity of the extracts. As applied in this study, the Ames assay can serve as a sensitive test for screening the mutagenic potential of large numbers of uncharacterized sediment extracts.
Antimutagenic and anticarcinogenic effects of betel leaf extract against the tobacco-specific nitrosamine 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK).

PubMed

Bhide, S V; Padma, P R; Amonkar, A J

1991-01-01

Earlier studies showed that betel leaf inhibits the mutagenic action of standard mutagens like benzo[a]pyrene and dimethylbenz[a]anthracene. Since tobacco-specific nitrosamines are the major carcinogens present in unburnt forms of tobacco, we studied the effect of an extract of betel leaf on the mutagenic and carcinogenic actions of one of the most potent, 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK). Betel-leaf extract and hydroxychavicol suppressed the mutagenicity of NNK in both the Ames and the micronucleus test. In studies in mice, betel-leaf extract reduced the tumorigenic effects of NNK by 25%. Concurrent treatment with the extract also inhibited the decreases in levels of vitamin A in liver and plasma induced by NNK. Betel leaf thus has protective effects against the mutagenic, carcinogenic and adverse metabolic effects of NNK in mice.
Oxygen radical-mediated mutagenic effect of asbestos on human lymphocytes: suppression by oxygen radical scavengers.

PubMed

Korkina, L G; Durnev, A D; Suslova, T B; Cheremisina, Z P; Daugel-Dauge, N O; Afanas'ev, I B

1992-02-01

The mutagenic effect of chrysotile asbestos fibers and zeolite and latex particles on human lymphocytes in whole blood has been studied. It was concluded that their mutagenic activities were mediated by oxygen radicals because they were inhibited by antioxidant enzymes (SOD and catalase) and oxygen radical scavengers (rutin, ascorbic acid, and bemitil). It was proposed that oxygen radicals were released by phagocytes activated upon exposure to mineral dusts and fibers. The study of lucigenin- and luminol-amplified chemiluminescence of peritoneal macrophages stimulated by chrysotile fibers and zeolite and latex particles has shown that their mutagenic action is probably mediated by different oxygen species, namely, by the iron-oxygen complexes (perferryl ions) plus hydrogen peroxide, hydrogen peroxide, and superoxide ion, respectively. From the oxygen radical scavengers studied, rutin was the most effective inhibitor of the mutagenic effect of mineral fibers and dusts.
Solution to the SLAM problem in low dynamic environments using a pose graph and an RGB-D sensor.

PubMed

Lee, Donghwa; Myung, Hyun

2014-07-11

In this study, we propose a solution to the simultaneous localization and mapping (SLAM) problem in low dynamic environments by using a pose graph and an RGB-D (red-green-blue depth) sensor. The low dynamic environments refer to situations in which the positions of objects change over long intervals. Therefore, in the low dynamic environments, robots have difficulty recognizing the repositioning of objects unlike in highly dynamic environments in which relatively fast-moving objects can be detected using a variety of moving object detection algorithms. The changes in the environments then cause groups of false loop closing when the same moved objects are observed for a while, which means that conventional SLAM algorithms produce incorrect results. To address this problem, we propose a novel SLAM method that handles low dynamic environments. The proposed method uses a pose graph structure and an RGB-D sensor. First, to prune the falsely grouped constraints efficiently, nodes of the graph, that represent robot poses, are grouped according to the grouping rules with noise covariances. Next, false constraints of the pose graph are pruned according to an error metric based on the grouped nodes. The pose graph structure is reoptimized after eliminating the false information, and the corrected localization and mapping results are obtained. The performance of the method was validated in real experiments using a mobile robot system.
Engaging in Problem Posing Activities in a Dynamic Geometry Setting and the Development of Prospective Teachers' Mathematical Knowledge

ERIC Educational Resources Information Center

Lavy, Ilana; Shriki, Atara

2010-01-01

In the present study we explore changes in perceptions of our class of prospective mathematics teachers (PTs) regarding their mathematical knowledge. The PTs engaged in problem posing activities in geometry, using the "What If Not?" (WIN) strategy, as part of their work on computerized inquiry-based activities. Data received from the PTs'…

Mathematical Problem Posing as a Measure of Curricular Effect on Students' Learning

ERIC Educational Resources Information Center

Cai, Jinfa; Moyer, John C.; Wang, Ning; Hwang, Stephen; Nie, Bikai; Garber, Tammy

2013-01-01

In this study, we used problem posing as a measure of the effect of middle-school curriculum on students' learning in high school. Students who had used a standards-based curriculum in middle school performed equally well or better in high school than students who had used more traditional curricula. The findings from this study not only show…
Personal thoughts on the future of the Environmental Mutagen Society.

PubMed

Brusick, D

1994-01-01

The Environmental Mutagen Society (EMS) was one of the first professional scientific societies organized to respond to an environmental concern. The threat of environmental pollution stimulated the formation of the organization in 1969. The Society's mission was to create a forum for discussion of methods and strategies to deal with mutagenic agents formed and/or released into the environment. During the past 25 years, EMS has provided a forum for innovation and scientific discussions. The Environmental Mutagen Society, and, in particular, its applied role in genetic toxicology, has had a profound positive impact on many disciplines in toxicology and safety assessment (i.e., carcinogenesis and in vitro alternatives.
Mutagenicity of airborne particulates in the rubber industry.

PubMed

Barański, B; Indulski, J; Janik-Spiechowicz, E; Palus, J

1989-12-01

The aim of this work was to evaluate the mutagenic activity of airborne particulate matter in the rubber industry. Air was sucked through Whatman glass-fibre filters with Staplex pumps and adsorbed substances and fume particles were extracted with acetone or toluene for 2 h in a ultrasonic cleaner. After separation of the insoluble solid phase by filtration, solvent was evaporated at a temperature of 70 degrees C in an argon atmosphere. The residue was stored at -20 degrees C. Mutagenicity was determined by the Salmonella plate incorporation assay with the tester strain TA98 and activity is related either to the weight of aerosol (rev mg-1) or to the volume of atmospheric sample (rev m-3). The fumes emitted from the tyre tread line, calender feeding, and tyre vulcanizing processes, showed the highest mutagenic activity (55-211 rev mg-1, + S9). At these and at other workplaces (extruder mill, carbon black station, mixer loading), mutagenic activity related to the volume of air was in the range of 22-158 rev m-3, + S9. The results indicate the need to reduce and monitor mutagenic contamination in order to increase the safety of work in the rubber industry.
Antimutagenicity of WR-1065 in L5178Y cells exposed to accelerated (56)Fe ions

NASA Technical Reports Server (NTRS)

Evans, H. H.; Evans, T. E.; Horng, M. F.

2002-01-01

The ability of the aminothiol WR-1065 [N-(2-mercaptoethyl)-1,3-diaminopropane] to protect L5178Y (LY) cells against the cytotoxic and mutagenic effects of exposure to accelerated (56)Fe ions (1.08 GeV/nucleon) was determined. It was found that while WR-1065 reduced the mutagenicity in both cell lines when it was present during the irradiation, the addition of WR-1065 after the exposure had no effect on the mutagenicity of the radiation in either cell line. No marked protection against the cytotoxic effects of exposure to (56)Fe ions was provided by WR-1065 when added either during or after irradiation in either cell line. We reported previously that WR-1065 protected the LY-S1 and LY-SR1 cell lines against both the cytotoxicity and mutagenicity of X radiation when present during exposure, but that its protection when administered after exposure was limited to the mutagenic effects in the radiation-hypersensitive cell line, LY-S1. The results indicate that the mechanisms involved differ in the protection against cytotoxic compared to mutagenic effects and in the protection against damage caused by accelerated (56)Fe ions compared to X radiation.
In vivo metabolism and genotoxic effects of nitrated polycyclic aromatic hydrocarbons.

PubMed

Möller, L

1994-10-01

During incomplete combustion of organic matter, nitro-polycyclic aromatic hydrocarbons (nitro-PAHs), are formed in a reaction that is catalyzed by a low pH. 2-Nitrofluorene (NF), a marker for nitro-PAHs, is metabolized in vivo by two different routes. After inhalation, potent mutagenic metabolites, hydroxylated nitrofluorenes (OH-NFs), are formed. The metabolites are distributed by systemic circulation. After oral administration, NF is reduced to the corresponding amine, a reaction mediated by the intestinal microflora. This metabolite is acetylated to 2-acetylaminofluorene (AAF), a potent carcinogen. Further ring-hydroxylation of AAF leads to detoxification and excretion. Induction of cytochrome P450s affects the metabolism, and more OH-NFs are formed. As a consequence, more mutagenic metabolites are found in the circulation. OH-NFs are excreted in the bile as, in terms of mutagenicity, totally harmless glucuronide conjugates. When these conjugates are excreted via the bile, intestinal beta-glucuronidase can liberate direct-acting mutagens in the intestine. Thus, inhalation of NF can lead to formation of potent mutagens in the intestine. NF is a direct-acting mutagen in bacterial assays and an initiator and promoter of the carcinogenic process, and gives rise to DNA adduct formation in laboratory animals.
Mutagenicity of 1-nitropyrene metabolites from lung S9.

PubMed

King, L C; Kohan, M J; Ball, L M; Lewtas, J

1984-04-01

The mutagenicity of 1-nitropyrene metabolites from rabbit lung S9 incubates was evaluated using the Salmonella typhimurium plate incorporation assay with strain TA98, with and without Aroclor-induced rat liver S9. The following metabolites were isolated, identified and quantitated by HPLC: 1-nitropyrene -4,5- or -9,10-dihydrodiol (K-DHD), N-acetyl-1-aminopyrene ( NAAP ), 1-aminopyrene (1-AMP), 10-hydroxy-1-nitropyrene, 4-, 5-, 6-, 8- or 9-monohydroxy-1-nitropyrene (phenols) and 3-hydroxy-1-nitropyrene. The predominant metabolites formed by lung S9 incubates were K-DHD, 3-OH-1-nitropyrene and phenols. All of the metabolites were mutagenic in the absence of the exogenous rat liver S9 metabolic activation system, and several, including two unidentified metabolites were more potent than the parent 1-nitropyrene. The mutagenicity of 3 of the metabolites ( NAAP , 10-OH-1-nitropyrene and phenols) were enhanced by S9 while most of the other metabolites were less mutagenic in the presence of S9. These results indicate that lung tissue is capable of both oxidative and reductive metabolism which produced mutagenic metabolites, several of which were more potent than the parent compound, 1-NP.
Mutagens in cooked foods - metabolism and genetic toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Felton, J.S.; Bjeldanes, L.F.; Hatch, F.T.

1984-02-17

Recently developed in our laboratories is an efficient extraction procedure incorporating XAD resin adsorption which yields from 200/sup 0/C grilled ground beef an extract containing 230 Salmonella TA1538 revertants per g fresh weight of original ground beef. These mutagenic components are specific for frameshift-sensitive Salmonella strains and have an absolute requirement for metabolic activation. Normal-phase HPLC separation of methanol-extractable metabolites generated from reaction of 2-amino-3-methylimidazo (4,5-f)quinoline (IQ), a mutagenic component of broiled food with rat liver microsomes resulted in one direct-acting mutagenic peak and a second more polar peak still requiring metabolic activation. Two potent thermally-produced bacterial mutagens, 3-amino-1-methyl-5H-pyrido (4,3-b)more » indole (Trp-P-2) and IQ, were examined in mammalian cells. In excision repair-deficient CHO cells, Trp-P-2 exposure caused cytotoxicity, mutagenicity, sister chromatid exchange, and chromosomal aberrations at concentrations more than 30-fold lower than those for IQ. In normal repair-proficient CHO cells Trp-P-2 was one-half as active and IQ was inactive. Relative to Trp-P-2, IQ is much more potent in the Salmonella bacterial system than in mammalian CHO cells.« less
Mutagenicity testing of the antiparasitic drug entizol (polfa) in the detection system of Salmonella typhimurium mutants.

PubMed

Dobiás, L

1980-02-01

The mutagenic activity was tested of a clinically used drug Entizol (Polfa) which contains metronidazole as an active substance. The mutagenicity of the compound was detected for Salmonella typhimurium indicator strains TA100, TA1535, TA1950, and TA1538 in tests in vitro without metabolic activation at the concentration range of 180 to 1600 microgram per plate. Metabolic conversion of the preparation studied in vivo gave rise to mutagenic metabolites detectable in the blood of mice after both intraperitoneal and per-oral application. The presence of the products of drug metabolism in the blood of experimental animals was tested at 1-40 h intervals after application. Blood samples of mice treated intraperitoneally with single doses of 1470 and 35 mg/kg were tested in strains TA100 and TA98. There were differences in the times of occurrence of mutagenic metabolites. The development of two mutagenicity maxima, detected in the blood withdrawn within the interval of 60-120 min (Rt/Rc 3.1) and 19 h (Rt/Rc 24.8) after the application of a dose of 1470 mg/kg in the strain TA100, is characteristic. The mutagenic effect of the blood of animals treated with a dose of 35 mg/kg, which approximately corresponds to standard therapeutic values, also had an analogous character. The highest mutagenic effect was detected in blood samples withdrawn 19 h after application (Rt/Rc 15.8). The frameshift mutation-detecting strain TA98 reverted at a lower frequency (about 5 times) under the above conditions, but only during analysis of the blood samples of animals treated with a dose of 1470 mg/kg. These results indicate that, for assessing the mutagenicity of 5-nitroimidazole compounds and their metabolites in blood, it is necessary to analyse blood samples withdrawn at least up to 24 h after application of the compound. This relationship was not proved to exist between the frequencies of induced revertants during the testing of blood withdrawn within 1-24 h after single per-oral administration of the drug in a dose range of 500-62.5 mg/kg. However, the mutagenicity of blood metabolites for strain TA100 was demonstrated not earlier than 24 h after the application of Entizol at 500 and 250 mg/kg.
Urinary 1-hydroxypyrene and mutagenicity in bus drivers and mail carriers exposed to urban air pollution in Denmark.

PubMed

Hansen, Ase Marie; Wallin, Håkan; Binderup, Mona Lise; Dybdahl, Marianne; Autrup, Herman; Loft, Steffen; Knudsen, Lisbeth Ehlert

2004-01-10

Previous studies in Denmark have shown that bus drivers and tramway employees were at an increased risk for developing several types of cancer and that bus drives from central Copenhagen have high levels of biomarkers of DNA damage. The present study evaluates 1-hydroxypyrene concentrations and mutagenic activity in urine as biomarkers of exposure in non-smoking bus drivers in city and rural areas on a work day and a day off and in non-smoking mail carriers working outdoors (in the streets) and indoors (in the office). Twenty-four hour urine samples were collected on a working day and a day off from 60 non-smoking bus drivers in city and rural areas and from 88 non-smoking mail carriers working outdoors (in the streets) and indoors (in the office). The concentration of 1-hydroxypyrene was measured by means of HPLC and the mutagenic activity was assessed by the Ames assay with Salmonella tester strain YG1021 and S9 mix. The N-acetyltransferase (NAT2) phenotype was used as a biomarker for susceptibility to mutagenic/carcinogenic compounds. Bus drivers excreted more 1-hydroxypyrene in urine than did mail carriers. The differences were slightly smaller when NAT2 phenotype, cooking at home, exposure to vehicle exhaust, and performing physical exercise after work were included. The NAT2 slow acetylators had 29% (1.29 [CI: 1.15-1.98]) higher 1-hydroxypyrene concentrations in urine than the fast acetylators. Male bus drivers had 0.92 revertants/mol creatinine [CI: 0.37-1.47] and female bus drivers 1.90 revertants/mol creatinine [CI: 1.01-2.79] higher mutagenic activity in urine than mail carriers. The present study indicates that bus drivers are more exposed to polycyclic aromatic hydrocarbons (PAH) and mutagens than mail carriers. Mail carriers who worked outdoors had higher urinary concentration of 1-hydroxypyrene, a marker of exposure to PAH, than those working indoors. The individual levels of urinary mutagenic activity were not correlated to excretion of 1-hydroxypyrene. This might be due to the fact that the most potent mutagenic compounds in diesel exhaust are not PAH but dinitro-pyrenes. Among bus drivers, fast NAT2 acetylators had higher mutagenic activity in urine than slow NAT2 acetylators and female bus drivers had higher mutagenic activity than male bus drivers.
Pose-Invariant Face Recognition via RGB-D Images.

PubMed

Sang, Gaoli; Li, Jing; Zhao, Qijun

2016-01-01

Three-dimensional (3D) face models can intrinsically handle large pose face recognition problem. In this paper, we propose a novel pose-invariant face recognition method via RGB-D images. By employing depth, our method is able to handle self-occlusion and deformation, both of which are challenging problems in two-dimensional (2D) face recognition. Texture images in the gallery can be rendered to the same view as the probe via depth. Meanwhile, depth is also used for similarity measure via frontalization and symmetric filling. Finally, both texture and depth contribute to the final identity estimation. Experiments on Bosphorus, CurtinFaces, Eurecom, and Kiwi databases demonstrate that the additional depth information has improved the performance of face recognition with large pose variations and under even more challenging conditions.
Mutagenicity of diesel exhaust particles from an engine with differing exhaust after treatments.

PubMed

Shi, X-C; Keane, M J; Ong, T; Li, S-Q; Bugarski, A B

2010-01-01

This study was conducted to investigate the effects of engine operating conditions and exhaust aftertreatments on the mutagenicity of diesel particulate matter (DPM) collected directly in an underground mine environment. A number of after-treatment devices are currently used on diesel engines in mines, but it is critical to determine whether reductions in DPM concentrations result in a corresponding decrease in adverse health effects. An eddy-current dynamometer was used to operate naturally aspirated mechanically controlled engine at several steady-state conditions. The samples were collected when the engine was equipped with a standard muffler, a diesel oxidation catalytic converter, two types of uncatalyzed diesel particulate filter systems, and three types of disposable diesel particulate filter elements. Bacterial gene mutation activity of DPM was tested on acetone extracts using the Ames Salmonella assay. The results indicated strong correlation between engine operating conditions and mutagenic activity of DPM. When the engine was fitted with muffler, the mutagenic activity was observed for the samples collected from light-load, but not heavy-load operating conditions. When the engine was equipped with a diesel oxidation catalyst, the samples did not exhibit mutagenic activity for any of four engine operating conditions. Mutagenic activity was observed for the samples collected when the engine was retrofitted with three types of disposable filters and sintered metal diesel particulate filter and operated at light load conditions. However, those filtration systems substantially reduced the concentration-normalized mutagenic activity from the levels observed for the muffler.
Investigation of toxicity and mutagenicity of cold atmospheric argon plasma.

PubMed

Maisch, T; Bosserhoff, A K; Unger, P; Heider, J; Shimizu, T; Zimmermann, J L; Morfill, G E; Landthaler, M; Karrer, S

2017-04-01

Cold atmospheric argon plasma is recognized as a new contact free approach for the decrease of bacterial load on chronic wounds in patients. So far very limited data are available on its toxicity and mutagenicity on eukaryotic cells. Thus, the toxic/mutagenic potential of cold atmospheric argon plasma using the MicroPlaSter β ® , which has been used efficiently in humans treating chronic and acute wounds, was investigated using the XTT assay in keratinocytes and fibroblasts and the HGPRT (hypoxanthine guanine phosphoribosyl transferase) assay with V79 Chinese hamster cells. The tested clinical parameter of a 2 min cold atmospheric argon plasma treatment revealed no relevant toxicity on keratinocytes (viability: 76% ± 0.17%) and on fibroblasts (viability: 81.8 ± 0.10) after 72 hr as compared to the untreated controls. No mutagenicity was detected in the HGPRT assay with V79 cells even after repetitive CAP treatments of 2-10 min every 24 hr for up to 5 days. In contrast, UV-C irradiation of V79 cells, used as a positive control in the HGPRT test, led to DNA damage and mutagenic effects. Our findings indicate that cold atmospheric plasma using the MicroPlaSter β ® shows negligible effects on keratinocytes and fibroblasts but no mutagenic potential in the HGPRT assay, indicating a new contact free safe technology. Environ. Mol. Mutagen. 58:172-177, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Nitroreductase-dependent mutagenicity of p-nitrophenylhydroxylamine and its N-acetyl and N-formyl hydroxamic acids.

PubMed

Corbett, M D; Wei, C; Corbett, B R

1985-05-01

p-Nitrophenylhydroxylamine (NPH) and two hydroxamic acids derived from it were synthesized and subjected to mutagenicity testing in Salmonella typhimurium strains TA98, TA98NR, TA1538 and TA1538NR. In addition, p-dinitrobenzene (DNB), p-nitroaniline (NA) and p-nitroacetanilide (AcNA) were simultaneously examined for mutagenic action against these four tester strains. NPH, its N-acetyl (AcNPH) and N-formyl (FoNPH) derivatives, and also DNB displayed strong mutagenic action to the nitroreductase-containing strains, TA98 and TA1538. NPH was the most potent chemical in this series against both of these strains, while the two hydroxamic acids AcNPH and FoNPH, and also DNB displayed approximately the same degree of mutagenicity. In the nitroreductase-deficient strains, TA98NR and TA1538NR, the mutagenicity of these four compounds was markedly reduced. The necessity for nitroreduction in order to activate these promutagens is fairly certain; however, the lack of mutagenicity of NA and AcNA towards all four tester strains made the interpretation of these data somewhat more complicated. Several possible bioactivation pathways were presented, with one mechanism in particular being proposed. This mechanism requires only that the strong electron-withdrawing nitro group be converted to an electron-donating group by bacterial nitroreductase. Such a mechanism is unique for the bioactivation of nitro aromatics by nitroreductase, since the enzymatic reduction need not produce the intermediary hydroxylamine metabolite.
An investigation of interurban variations in the chemical composition and mutagenic activity of airborne particulate organic matter using an integrated chemical class/bioassay system

NASA Astrophysics Data System (ADS)

Butler, J. P.; Kneip, T. J.; Daisey, J. M.

Previous investigations in this laboratory have demonstrated that the mutagenic activities of extractable particulate organic matter (EOM) from cities which differ in their principal fuels and meteorology can vary significantly. To gain a better understanding of these interurban variations, an Integrated Chemical Class/Biological Screening System was developed and used for a more detailed examination of differences in the chemical composition and mutagenic activity of EOM. The screening system involved coupling in situ Ames mutagenicity determinations on high performance thin layer chromatography (HPTLC) plates with class specific chemical analyses on a second set of plates. The system was used to screen for mutagenic activity and selected chemical classes (including PAH, nitro-PAH, phenols, carboxylic acids, carbonyls, aza-arenes and alkylating agents) in EOM from the following sites: New York City; Elizabeth, N.J.; Mexico City; Beijing, China; Philadelphia, PA; and the Caldecott Tunnel (CA). The results of this study demonstrated mutagenic activity and chemical compositional differences in HPTLC subfractions of particulate organic matter from these cities and from the Caldecott Tunnel. The greatest interurban differences in chemical classes were observed for the phenols, carbonyl compounds and alkylating agents. Interurban variations in mutagenic activities were greatest for EOM subfractions of intermediate polarity. These differences are probably related to interurban differences in the fuels used, types of sources and atmospheric conditions. The relationships between these variables are not well understood at present.
Evaluation of micronuclei induction capacity and mutagenicity of organochlorine and organophosphate pesticides.

PubMed

Yaduvanshi, Santosh K; Srivastava, Nalini; Marotta, Francesco; Jain, Shalini; Yadav, Hariom

2012-09-01

The genotoxic and mutagenic effects of two commonly used organochlorine pesticides, lindane (LND) and endosulfan (ENS), and two commonly used organophosphate pesticides, chlorpyrifos (CPF) and monocrotophos (MCP) were assessed using in vivo mouse bone marrow micronucleus test and in vitro Ames Salmonella/ microsome mutagenicity test. The results showed that these pesticides alone or in combination, induced significantly high frequency of micronuclei (MN) formation that increased with concentration of pesticides. All these four pesticides produced significant increase in the frequencies of micronucleated-polychromatic erythrocytes (MN-PCE) and decrease infrequencies of PCE in dose-dependent manner. The results indicate the suppression of proliferative activity of the bone marrow and increase in the extent of cell death. ENS and MCP showed mutagenic potential in Salmonella/ microsome assay. ENS induced mutagenic and nontoxic response only in TA98 tester strain of S.typhimurium at the dose of 500 μg/plate and in the absence of metabolic activation. MCP showed weak mutagenic and nontoxic effect only in TA100 tester strain at the dose of 5000 μg/plate in both assays, with or without metabolic activation when compared with negative control. MCP was toxic in TA98 tester strain at the dose of 5000 μg/plate in absence of metabolic activation while reduction in toxicity was seen on addition of S9 mixture. The study clearly showed the genotoxic potential of all these four pesticides and mutagenic response of endosulfan and monocrotophos.
[Mutagenic evaluation of the urine of rats treated with oils implicated in the toxic oil syndrome using bacterial tests].

PubMed

Barrueco, C; Sladek, F; Canga, C; Valcarce, E; de la Peña, E; Alia, M; Laborda, E

1983-01-01

The mutagenic activity of the urine of pregnant rats treated with toxic oil syndrome-related rape seed oil or with edible oil was evaluated by means of the Ames and Green tests. It was found that the urine of the pregnant rats treated with "Jen" oil, that was related to the toxic oil syndrome, was mutagenic.
Comprehensive progress report, July 1, 1974-September 30, 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ames, B. N.

1977-05-01

Comprehensive research progress for the period July 1974 through September 1977 is reported. The objectives are to develop a set of bacterial strains that can be used to screen pesticides, herbicides, food additives, drugs, etc. for mutagens and to use these strains for investigating the mode of action of various mutagens and in particular for finding mutagens that make specific changes in DNA. (ACR)
MX [3-Chloro-4-(Dichloromethyl)-5-Hydroxy-2[5H]-Furanone], A Drinking-Water Carcinogen, Does Not Induce Mutations in the Liver of Cii Transgenic Medaka (Oryzias latipes)

EPA Science Inventory

Mutagenicity assays with Salmonella have shown that 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone (MX), a drinking water disinfection by-product is a potent mutagen, accounting for about one third of the mutagenic potency/potential of chlorinated drinking water. The abilit...
Mutagenicity of biodiesel or diesel exhaust particles and the effect of engine operating conditions.

PubMed

Kisin, Elena R; Shi, X C; Keane, Michael J; Bugarski, Aleksandar B; Shvedova, Anna A

2013-03-01

Changing the fuel supply from petroleum based ultra-low sulfur diesel (ULSD) to biodiesel and its blends is considered by many to be a viable option for controlling exposures to particulate material (PM). This is critical in the mining industry where approximately 28,000 underground miners are potentially exposed to relatively high concentrations of diesel particulate matter (DPM). This study was conducted to investigate the mutagenic potential of diesel engine emissions (DEE) from neat (B100) and blended (B50) soy-based fatty acid methyl ester (FAME) biodiesel in comparison with ULSD PM using different engine operating conditions and exhaust aftertreatment configurations. The DPM samples were collected for engine equipped with either a standard muffler or a combination of the muffler and diesel oxidation catalytic converter (DOC) that was operated at four different steady-state modes. Bacterial gene mutation activity of DPM was tested on the organic solvent extracts using the Ames Salmonella assay. The results indicate that mutagenic activity of DPM was strongly affected by fuels, engine operating conditions, and exhaust aftertreatment systems. The mutagenicity was increased with the fraction of biodiesel in the fuel. While the mutagenic activity was observed in B50 and B100 samples collected from both light-and heavy-load operating conditions, the ULSD samples were mutagenic only at light-load conditions. The presence of DOC in the exhaust system resulted in the decreased mutagenicity when engine was fueled with B100 and B50 and operated at light-load conditions. This was not the case when engine was fueled with ULSD. Heavy-load operating condition in the presence of DOC resulted in a decrease of mutagenicity only when engine was fueled with B50, but not B100 or ULSD. Therefore, the results indicate that DPM from neat or blended biodiesel has a higher mutagenic potency than that one of ULSD. Further research is needed to investigate the health effect of biodiesel as well as efficiency of DOC or other exhaust aftertreatment systems.
Mutagenicity of biodiesel or diesel exhaust particles and the effect of engine operating conditions

PubMed Central

Kisin, Elena R; Shi, X.C; Keane, Michael J; Bugarski, Aleksandar B; Shvedova, Anna A

2015-01-01

Background Changing the fuel supply from petroleum based ultra-low sulfur diesel (ULSD) to biodiesel and its blends is considered by many to be a viable option for controlling exposures to particulate material (PM). This is critical in the mining industry where approximately 28,000 underground miners are potentially exposed to relatively high concentrations of diesel particulate matter (DPM). This study was conducted to investigate the mutagenic potential of diesel engine emissions (DEE) from neat (B100) and blended (B50) soy-based fatty acid methyl ester (FAME) biodiesel in comparison with ULSD PM using different engine operating conditions and exhaust aftertreatment configurations. Methods The DPM samples were collected for engine equipped with either a standard muffler or a combination of the muffler and diesel oxidation catalytic converter (DOC) that was operated at four different steady-state modes. Bacterial gene mutation activity of DPM was tested on the organic solvent extracts using the Ames Salmonella assay. Results The results indicate that mutagenic activity of DPM was strongly affected by fuels, engine operating conditions, and exhaust aftertreatment systems. The mutagenicity was increased with the fraction of biodiesel in the fuel. While the mutagenic activity was observed in B50 and B100 samples collected from both light-and heavy-load operating conditions, the ULSD samples were mutagenic only at light-load conditions. The presence of DOC in the exhaust system resulted in the decreased mutagenicity when engine was fueled with B100 and B50 and operated at light-load conditions. This was not the case when engine was fueled with ULSD. Heavy-load operating condition in the presence of DOC resulted in a decrease of mutagenicity only when engine was fueled with B50, but not B100 or ULSD. Conclusions Therefore, the results indicate that DPM from neat or blended biodiesel has a higher mutagenic potency than that one of ULSD. Further research is needed to investigate the health effect of biodiesel as well as efficiency of DOC or other exhaust aftertreatment systems. PMID:26457185

Ethanol- or acetone-pretreatment of mice strongly enhances the bacterial mutagenicity of dimethylnitrosamine in assays mediated by liver subcellular fraction, but not in host-mediated assays.

PubMed

Glatt, H; de Balle, L; Oesch, F

1981-01-01

The activation of dimethylnitrosamine (DMN) to a bacterial mutagen in liver subcellular fraction and in intrasanguinous host-mediated assays was studied, in particular the effect of pretreatment of the animals with ethanol or acetone. Salmonella typhimurium TA 92 was much more sensitive to DMN mutagenicity than TA 100 and TA 1535 or Escherichia coli WP2uvrA and was used for the main part of the study. Noteworthy, in part already known, features of the in vitro activation are the relatively low pH optimum (pH 6-6.4), the non-linear dose-mutagenic response-relationship and the relatively high doses of DMN required for activation with control preparations. Pretreatment of mice with ethanol or acetone greatly reduced the minimal mutagenically effective concentration of DMN in the in vitro assay. Pretreatment with Aroclor 1254, an inducer frequently used in mutagenicity research, showed little effect when used alone, but reduced the potentiation by acetone. The results of the host-mediated assays substantially differed from those of the in vitro activation assays (a) in the relatively low dose of DMN required for mutagenicity to occur and (b) in the lack of potentiation by acetone-or ethanol-pretreatment. Acetone even led to a marginal decrease in mutagenicity. As a possible explantation for this apparent discrepancy were assume that with the in vitro system the activity of the dilute metabolizing system is limiting for the activation of DMN and induction therefore will increase the mutagenicity, whereas in vivo DMN is quantitatively metabolized in both induced and non-induced animals. The results show that caution has to be taken in the interpretation from in vitro results to the in vivo situation. In particular our in vivo experiments do not support the hypothesis that the induction by ethanol of an activating system with a low Km (which would strongly activate traces of DMN ingested with many foods) is one of the reasons for the increased risk of liver tumors in alcoholics.
Mutagenicity and clastogenicity of extracts of Helicobacter pylori detected by the Ames test and in the micronucleus test using human lymphoblastoid cells.

PubMed

Arimoto-Kobayashi, Sakae; Ohta, Kaori; Yuhara, Yuta; Ayabe, Yuka; Negishi, Tomoe; Okamoto, Keinosuke; Nakajima, Yoshihiro; Ishikawa, Takeshi; Oguma, Keiji; Otsuka, Takanao

2015-07-01

Epidemiological studies have demonstrated a close association between infection with Helicobacter pylori (H.pylori) and the development of gastric carcinoma. Chronic H.pylori infection increases the frequency of mutation in gastric epithelial cells. However, the mechanism by which infection of H.pylori leads to mutation in gastric epithelial cells is unclear. We suspected that components in H.pylori may be related to the mutagenic response associated with DNA alkylation, and could be detected with the Ames test using a more sensitive strain for alkylating agents. Our investigation revealed that an extract of H.pylori was mutagenic in the Ames test with Salmonella typhimurium YG7108, which is deficient in the DNA repair of O(6)-methylguanine. The extract of H.pylori may contain methylating or alkylating agents, which might induce O (6)-alkylguanine in DNA. Mutagenicity of the alkylating agents N-methyl-N-nitrosourea (MNU) and N-methyl-N'-nitro-N-nitrosoguanidine in the Ames test with S.typhimurium TA1535 was enhanced significantly in the presence of the extract of H.pylori. The tested extracts of H.pylori resulted in a significant induction of micronuclei in human-derived lymphoblastoid cells. Heat instability and dialysis resistance of the extracts of H.pylori suggest that the mutagenic component in the extracts of H.pylori is a heat-unstable large molecule or a heat-labile small molecule strongly attached or adsorbed to a large molecule. Proteins in the extracts of H.pylori were subsequently fractionated using ammonium sulphate precipitation. However, all fractions expressed enhancing effects toward MNU mutagenicity. These results suggest the mutagenic component is a small molecule that is absorbed into proteins in the extract of H.pylori, which resist dialysis. Continuous and chronic exposure of gastric epithelial cells to the alkylative mutagenic component from H.pylori chronically infected in the stomach might be a causal factor in the gastric carcinogenesis associated with H.pylori. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
[Evaluation of Educational Effect of Problem-Posing System in Nursing Processing Study].

PubMed

Tsuji, Keiko; Takano, Yasuomi; Yamakawa, Hiroto; Kaneko, Daisuke; Takai, Kiyako; Kodama, Hiromi; Hagiwara, Tomoko; Komatsugawa, Hiroshi

2015-09-01

The nursing processing study is generally difficult, because it is important for nursing college students to understand knowledge and utilize it. We have developed an integrated system to understand, utilize, and share knowledge. We added a problem-posing function to this system, and expected that students would deeply understand the nursing processing study through the new system. This system consisted of four steps: create a problem, create an answer input section, create a hint, and verification. Nursing students created problems related to nursing processing by this system. When we gave a lecture on the nursing processing for second year students of A university, we tried to use the creating problem function of this system. We evaluated the effect by the number of problems and the contents of the created problem, that is, whether the contents consisted of a lecture stage or not. We also evaluated the correlation between those and regular examination and report scores. We derived the following: 1. weak correlation between the number of created problems and report score (r=0.27), 2. significant differences between regular examination and report scores of students who created problems corresponding to the learning stage, and those of students who created problems not corresponding to it (P<0.05). From these results, problem-posing is suggested to be effective to fix and utilize knowledge in the lecture of nursing processing theory.
The Effect of Problem Posing Oriented Analyses-II Course on the Attitudes toward Mathematics and Mathematics Self-Efficacy of Elementary Prospective Mathematics Teachers

ERIC Educational Resources Information Center

Akay, Hayri; Boz, Nihat

2010-01-01

Research on mathematics teaching and learning has recently focused on affective variables, which were found to play an essential role that influences behaviour and learning. Despite its importance, problem posing has not yet received the attention it warrants from the mathematics education community. Perceived self-efficacy beliefs have been found…
Mutagenicity of diesel engine exhaust is eliminated in the gas phase by an oxidation catalyst but only slightly reduced in the particle phase.

PubMed

Westphal, Götz A; Krahl, Jürgen; Munack, Axel; Ruschel, Yvonne; Schröder, Olaf; Hallier, Ernst; Brüning, Thomas; Bünger, Jürgen

2012-06-05

Concerns about adverse health effects of diesel engine emissions prompted strong efforts to minimize this hazard, including exhaust treatment by diesel oxidation catalysts (DOC). The effectiveness of such measures is usually assessed by the analysis of the legally regulated exhaust components. In recent years additional analytical and toxicological tests were included in the test panel with the aim to fill possible analytical gaps, for example, mutagenic potency of polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nPAH). This investigation focuses on the effect of a DOC on health hazards from combustion of four different fuels: rapeseed methyl ester (RME), common mineral diesel fuel (DF), SHELL V-Power Diesel (V-Power), and ARAL Ultimate Diesel containing 5% RME (B5ULT). We applied the European Stationary Cycle (ESC) to a 6.4 L turbo-charged heavy load engine fulfilling the EURO III standard. The engine was operated with and without DOC. Besides regulated emissions we measured particle size and number distributions, determined the soluble and solid fractions of the particles and characterized the bacterial mutagenicity in the gas phase and the particles of the exhaust. The effectiveness of the DOC differed strongly in regard to the different exhaust constituents: Total hydrocarbons were reduced up to 90% and carbon monoxide up to 98%, whereas nitrogen oxides (NO(X)) remained almost unaffected. Total particle mass (TPM) was reduced by 50% with DOC in common petrol diesel fuel and by 30% in the other fuels. This effect was mainly due to a reduction of the soluble organic particle fraction. The DOC caused an increase of the water-soluble fraction in the exhaust of RME, V-Power, and B5ULT, as well as a pronounced increase of nitrate in all exhausts. A high proportion of ultrafine particles (10-30 nm) in RME exhaust could be ascribed to vaporizable particles. Mutagenicity of the exhaust was low compared to previous investigations. The DOC reduced mutagenic effects most effectively in the gas phase. Mutagenicity of particle extracts was less efficiently diminished. No significant differences of mutagenic effects were observed among the tested fuels. In conclusion, the benefits of the DOC concern regulated emissions except NO(X) as well as nonregulated emissions such as the mutagenicity of the exhaust. The reduction of mutagenicity was particularly observed in the condensates of the gas phase. This is probably due to better accessibility of gaseous mutagenic compounds during the passage of the DOC in contrast to the particle-bound mutagens. Concerning the particulate emissions DOC especially decreased ultrafine particles.
Correlations of water quality parameters with mutagenicity of chlorinated drinking water samples.

PubMed

Schenck, Kathleen M; Sivaganesan, Mano; Rice, Glenn E

2009-01-01

Adverse health effects that may result from chronic exposure to mixtures of disinfection by-products (DBPs) present in drinking waters may be linked to both the types and concentrations of DBPs present. Depending on the characteristics of the source water and treatment processes used, both types and concentrations of DBPs found in drinking waters vary substantially. The composition of a drinking-water mixture also may change during distribution. This study evaluated the relationships between mutagenicity, using the Ames assay, and water quality parameters. The study included information on treatment, mutagenicity data, and water quality data for source waters, finished waters, and distribution samples collected from five full-scale drinking water treatment plants, which used chlorine exclusively for disinfection. Four of the plants used surface water sources and the fifth plant used groundwater. Correlations between mutagenicity and water quality parameters are presented. The highest correlation was observed between mutagenicity and the total organic halide concentrations in the treated samples.
Paving asphalt products exhibit a lack of carcinogenic and mutagenic activity.

PubMed

Goyak, Katy O; McKee, Richard H; Minsavage, Gary D; McGowan, Claude; Daughtrey, Wayne C; Freeman, James J

2011-10-01

A paving asphalt and a vacuum residuum (derived from crude oil by atmospheric and subsequent vacuum distillation and used as a blend stock for asphalt) were tested in skin carcinogenesis assays in mice and in optimized Ames assays for mutagenic activity. In the skin cancer tests, each substance was applied twice weekly for 104 weeks to the clipped backs of groups of 50 male C3H mice. Neither the paving asphalt nor the vacuum residuum (30% weight/volume and 75% weight/weight in US Pharmacopeia mineral oil, respectively) produced any tumors. The positive control benzo[a]pyrene (0.05% w/v in toluene) induced tumors in 46 of 50 mice, demonstrating the effectiveness of the test method. Salmonella typhimurium tester strain TA98 was used in the optimized Ames assay to evaluate mutagenic potential. Dimethylsulfoxide (DMSO) extractions of the substances were not mutagenic when tested up to toxic limits. Thus, under the conditions of these studies, neither the paving asphalt nor the vacuum residuum was carcinogenic or mutagenic.
[Usefulness of the fruit fly for assessment of mutagenicity of benzene, acetaldehyde and formaldehyde].

PubMed

Krogulski, A

1994-01-01

Among the contaminants of water, soil and air the number of mutagenic and carcinogenic substances is increasing. For the assessment of health risk connected with the simple and cheap methods are necessary which could detected and measure the mutagenicity of these substances. The widely used tests using prokaryotes give negative results in the tests of certain substances which are carcinogenic in mammals. In the case of benzene and acetaldehyde Ames test gives false negative results, and in the case of formaldehyde the results are equivocal. An advantage of fruit fly Drosophila melanogaster used for this purpose is that its cell structures, enzymes and metabolic processes are similar to those of mammals. For the demonstration of mutagenicity of benzene, acetaldehyde and formaldehyde the test of somatic mutation and recombination SMART was carried out in these flies. The results confirmed the usefulness of the SMART test for the demonstration of the mutagenicity of contaminants in the environment.
One Answer to "What Is Calculus?"

ERIC Educational Resources Information Center

Shilgalis, Thomas W.

1979-01-01

A number of questions are posed that can be answered with the aid of calculus. These include best value problems, best shape problems, problems involving integration, and growth and decay problems. (MP)
Pose-free structure from motion using depth from motion constraints.

PubMed

Zhang, Ji; Boutin, Mireille; Aliaga, Daniel G

2011-10-01

Structure from motion (SFM) is the problem of recovering the geometry of a scene from a stream of images taken from unknown viewpoints. One popular approach to estimate the geometry of a scene is to track scene features on several images and reconstruct their position in 3-D. During this process, the unknown camera pose must also be recovered. Unfortunately, recovering the pose can be an ill-conditioned problem which, in turn, can make the SFM problem difficult to solve accurately. We propose an alternative formulation of the SFM problem with fixed internal camera parameters known a priori. In this formulation, obtained by algebraic variable elimination, the external camera pose parameters do not appear. As a result, the problem is better conditioned in addition to involving much fewer variables. Variable elimination is done in three steps. First, we take the standard SFM equations in projective coordinates and eliminate the camera orientations from the equations. We then further eliminate the camera center positions. Finally, we also eliminate all 3-D point positions coordinates, except for their depths with respect to the camera center, thus obtaining a set of simple polynomial equations of degree two and three. We show that, when there are merely a few points and pictures, these "depth-only equations" can be solved in a global fashion using homotopy methods. We also show that, in general, these same equations can be used to formulate a pose-free cost function to refine SFM solutions in a way that is more accurate than by minimizing the total reprojection error, as done when using the bundle adjustment method. The generalization of our approach to the case of varying internal camera parameters is briefly discussed. © 2011 IEEE
Kaempferol, a mutagenic flavonol from Helichrysum simillimum.

PubMed

Elgorashi, Ee; van Heerden, Fr; van Staden, J

2008-11-01

Helichrysum simillimum is native to South Africa. It is used for the treatment of coughs, colds, fever, infections, headache, and menstrual pain. Extracts of this species showed mutagenic effects in the Salmonella/microsome assay. The aim of this study was to isolate and determine the mutagenic constituents of H. simillimum. Bioassay-guided fractionation of 90% aqueous methanol extracts, using Salmonella typhimurium TA98, led to the isolation of the flavonol kaempferol.
Cellular Mutagenicity and Heavy Metal Concentrations of Leachates Extracted from the Fly and Bottom Ash Derived from Municipal Solid Waste Incineration

PubMed Central

Chen, Po-Wen; Liu, Zhen-Shu; Wun, Min-Jie; Kuo, Tai-Chen

2016-01-01

Two incinerators in Taiwan have recently attempted to reuse the fly and bottom ash that they produce, but the mutagenicity of these types of ash has not yet been assessed. Therefore, we evaluated the mutagenicity of the ash with the Ames mutagenicity assay using the TA98, TA100, and TA1535 bacterial strains. We obtained three leachates from three leachants of varying pH values using the toxicity characteristic leaching procedure test recommended by the Taiwan Environmental Protection Agency (Taiwan EPA). We then performed the Ames assay on the harvested leachates. To evaluate the possible relationship between the presence of heavy metals and mutagenicity, the concentrations of five heavy metals (Cd, Cr, Cu, Pb, and Zn) in the leachates were also determined. The concentrations of Cd and Cr in the most acidic leachate from the precipitator fly ash and the Cd concentration in the most acidic leachate from the boiler fly ash exceeded the recommended limits. Notably, none of the nine leachates extracted from the boiler, precipitator, or bottom ashes displayed mutagenic activity. This data partially affirms the safety of the fly and bottom ash produced by certain incinerators. Therefore, the biotoxicity of leachates from recycled ash should be routinely monitored before reusing the ash. PMID:27827867
Identification of mammalian cell genotoxins in respirable diesel exhaust particles by bioassay-directed chemical analysis.

PubMed

Oh, Seung-Min; Chung, Kyu-Hyuck

2006-03-01

A bioassay-directed chemical analysis which consists of mammalian cell bioassays (comet assay, CBMN assay and EROD-microbioassay) in conjunction with analytical measurements was performed to identify the most biologically active compounds of the diesel exhaust particulate matters (DEPs) on mutagenic activity. These bioassay systems were suitable to estimate the mammalian genotoxic potentials of pollutants present in low concentrations in limited environmental samples, as is the case with DEPEs. The results from mutagenic assay showed that the aromatic and slightly polar fraction of DEPs induced chromosomal damage and DNA breakage in a non-cytotoxic dose. It was also revealed that indirect-acting mutagens may mainly contribute to the mutagenic effect of aromatic fraction via the enzyme metabolism system. In the aromatic fraction, several indirect-acting mutagenic PAHs such as dibenzo(a,h)anthracene, chrysene, and 1,2-benzanthracene were detected by GC-MS and the complex mixture effect of this fraction was quantified in terms of its biological-TCDD equivalent concentration (bio-TEQ) which was 32.82 bio-TEQ ng/g-DEPs by EROD-microbioassay. Conclusively, we confirmed that indirect-acting mutagens contained in aromatic fraction may be important causatives of the genotoxicity of extracts of DEPs by integrating the results obtained from a mammalian cell bioassay-directed fractionation.
Use of genotoxicity information in the development of integrated testing strategies (ITS) for skin sensitization.

PubMed

Mekenyan, Ovanes; Patlewicz, Grace; Dimitrova, Gergana; Kuseva, Chanita; Todorov, Milen; Stoeva, Stoyanka; Kotov, Stefan; Donner, E Maria

2010-10-18

Skin sensitization is an end point of concern for various legislation in the EU, including the seventh Amendment to the Cosmetics Directive and Registration Evaluation, Authorisation and Restriction of Chemicals (REACH). Since animal testing is a last resort for REACH or banned (from 2013 onward) for the Cosmetics Directive, the use of intelligent/integrated testing strategies (ITS) as an efficient means of gathering necessary information from alternative sources (e.g., in vitro, (Q)SARs, etc.) is gaining widespread interest. Previous studies have explored correlations between mutagenicity data and skin sensitization data as a means of exploiting information from surrogate end points. The work here compares the underlying chemical mechanisms for mutagenicity and skin sensitization in an effort to evaluate the role mutagenicity information can play as a predictor of skin sensitization potential. The Tissue Metabolism Simulator (TIMES) hybrid expert system was used to compare chemical mechanisms of both end points since it houses a comprehensive set of established structure-activity relationships for both skin sensitization and mutagenicity. The evaluation demonstrated that there is a great deal of overlap between skin sensitization and mutagenicity structural alerts and their underlying chemical mechanisms. The similarities and differences in chemical mechanisms are discussed in light of available experimental data. A number of new alerts for mutagenicity were also postulated for inclusion into TIMES. The results presented show that mutagenicity information can provide useful insights on skin sensitization potential as part of an ITS and should be considered prior to any in vivo skin sensitization testing being initiated.
Combusting vegetable oils in diesel engines: the impact of unsaturated fatty acids on particle emissions and mutagenic effects of the exhaust.

PubMed

Bünger, Jürgen; Bünger, Jörn F; Krahl, Jürgen; Munack, Axel; Schröder, Olaf; Brüning, Thomas; Hallier, Ernst; Westphal, Götz A

2016-06-01

High particle emissions and strong mutagenic effects were observed after combustion of vegetable oil in diesel engines. This study tested the hypothesis that these results are affected by the amount of unsaturated or polyunsaturated fatty acids of vegetable oils. Four different vegetable oils (coconut oil, CO; linseed oil, LO; palm tree oil, PO; and rapeseed oil, RO) and common diesel fuel (DF) were combusted in a heavy-duty diesel engine. The exhausts were investigated for particle emissions and mutagenic effects in direct comparison with emissions of DF. The engine was operated using the European Stationary Cycle. Particle masses were measured gravimetrically while mutagenicity was determined using the bacterial reverse mutation assay with tester strains TA98 and TA100. Combustion of LO caused the largest amount of total particulate matter (TPM). In comparison with DF, it particularly raised the soluble organic fraction (SOF). RO presented second highest TPM and SOF, followed by CO and PO, which were scarcely above DF. RO revealed the highest number of mutations of the vegetable oils closely followed by LO. PO was less mutagenic, but still induced stronger effects than DF. While TPM and SOF were strongly correlated with the content of polyunsaturated fatty acids in the vegetable oils, mutagenicity had a significant correlation with the amount of total unsaturated fatty acids. This study supports the hypothesis that numbers of double bounds in unsaturated fatty acids of vegetable oils combusted in diesel engines influence the amount of emitted particles and the mutagenicity of the exhaust. Further investigations have to elucidate the causal relationship.
Mutagenic activity and metabolites in the urine of workers exposed to trinitrotoluene (TNT).

PubMed Central

Ahlborg, G; Einistö, P; Sorsa, M

1988-01-01

Urine samples taken after work and after a free weekend from 50 workers employed in various activities in a chemical plant manufacturing explosives were analysed. On the basis of hygienic surveys, the subjects were divided into three categories of exposure to trinitrotoluene (TNT). The urine analyses consisted of gas chromatographic identification of TNT and its two metabolites, 4-ADNT and 2-ADNT, and a determination of the mutagenic activity. Two frame shift detector strains of Salmonella typhimurium were used, TA 98 and TA 98 NR, the latter being deficient in endogenous nitroreductase activity. On the basis of previous results on TNT mutagenicity, no exogeneous metabolic system was used to test the urine concentrates. Both tester strains showed that the mean urinary mutagenic activity was higher in the after work samples than in post weekend samples from the same subjects, showing that bacterial nitroreductase activity was not significantly responsible for the mutagenicity, although the response was higher with strain TA 98 than with TA 98 NR. The interindividual variation in urine mutagenicity was high, however, and the difference between the two sampling times was statistically significant (p less than 0.05) only for the high exposed group (workers in trotyl foundry and sieve house). Correlation between urinary mutagenicity and concentration of TNT in urine was poor; correlation was significant only with the urinary concentration of 4-ADNT. The correlation between urinary TNT and both metabolites was good (p less than 0.001). These results suggest that analysis of 4-ADNT in urine would be a sufficient biological measure for controlling exposure to TNT. PMID:3378017
Azo dyes in clothing textiles can be cleaved into a series of mutagenic aromatic amines which are not regulated yet.

PubMed

Brüschweiler, Beat J; Merlot, Cédric

2017-08-01

Azo dyes represent the by far most important class of textile dyes. Their biotransformation by various skin bacteria may release aromatic amines (AAs) which might be dermally absorbed to a major extent. Certain AAs are well known to have genotoxic and/or carcinogenic properties. Correspondingly, azo dyes releasing one of the 22 known carcinogenic AAs are banned from clothing textiles in the European Union. In the present study, we investigated the mutagenicity of 397 non-regulated AAs potentially released from the 470 known textile azo dyes. We identified 36 mutagenic AAs via publicly available databases. After predicting their mutagenicity potential using the method by Bentzien, we accordingly allocated them into different priority groups. Ames tests on 18 AAs of high priority showed that 4 substances (22%) (CASRN 84-67-3, 615-47-4, 3282-99-3, 15791-87-4) are mutagenic in the strain TA98 and/or TA100 with and/or without rat S9 mix. Overall, combining the information from the Ames tests and the publicly available data, we identified 40 mutagenic AAs being potential cleavage products of approximately 180 different parent azo dyes comprising 38% of the azo dyes in our database. The outcome of this study indicates that mutagenic AAs in textile azo dyes are of much higher concern than previously expected, which entails implications on the product design and possibly on the regulation of azo dyes in the future. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.
Multi-object segmentation using coupled nonparametric shape and relative pose priors

NASA Astrophysics Data System (ADS)

Uzunbas, Mustafa Gökhan; Soldea, Octavian; Çetin, Müjdat; Ünal, Gözde; Erçil, Aytül; Unay, Devrim; Ekin, Ahmet; Firat, Zeynep

2009-02-01

We present a new method for multi-object segmentation in a maximum a posteriori estimation framework. Our method is motivated by the observation that neighboring or coupling objects in images generate configurations and co-dependencies which could potentially aid in segmentation if properly exploited. Our approach employs coupled shape and inter-shape pose priors that are computed using training images in a nonparametric multi-variate kernel density estimation framework. The coupled shape prior is obtained by estimating the joint shape distribution of multiple objects and the inter-shape pose priors are modeled via standard moments. Based on such statistical models, we formulate an optimization problem for segmentation, which we solve by an algorithm based on active contours. Our technique provides significant improvements in the segmentation of weakly contrasted objects in a number of applications. In particular for medical image analysis, we use our method to extract brain Basal Ganglia structures, which are members of a complex multi-object system posing a challenging segmentation problem. We also apply our technique to the problem of handwritten character segmentation. Finally, we use our method to segment cars in urban scenes.
Identification of phototransformation products of thalidomide and mixture toxicity assessment: an experimental and quantitative structural activity relationships (QSAR) approach.

PubMed

Mahmoud, Waleed M M; Toolaram, Anju P; Menz, Jakob; Leder, Christoph; Schneider, Mandy; Kümmerer, Klaus

2014-02-01

The fate of thalidomide (TD) was investigated after irradiation with a medium-pressure Hg-lamp. The primary elimination of TD was monitored and structures of phototransformation products (PTPs) were assessed by LC-UV-FL-MS/MS. Environmentally relevant properties of TD and its PTPs as well as hydrolysis products (HTPs) were predicted using in silico QSAR models. Mutagenicity of TD and its PTPs was investigated in the Ames microplate format (MPF) aqua assay (Xenometrix, AG). Furthermore, a modified luminescent bacteria test (kinetic luminescent bacteria test (kinetic LBT)), using the luminescent bacteria species Vibrio fischeri, was applied for the initial screening of environmental toxicity. Additionally, toxicity of phthalimide, one of the identified PTPs, was investigated separately in the kinetic LBT. The UV irradiation eliminated TD itself without complete mineralization and led to the formation of several PTPs. TD and its PTPs did not exhibit mutagenic response in the Salmonella typhimurium strains TA 98, and TA 100 with and without metabolic activation. In contrast, QSAR analysis of PTPs and HTPs provided evidence for mutagenicity, genotoxicity and carcinogenicity using additional endpoints in silico software. QSAR analysis of different ecotoxicological endpoints, such as acute toxicity towards V. fischeri, provided positive alerts for several identified PTPs and HTPs. This was partially confirmed by the results of the kinetic LBT, in which a steady increase of acute and chronic toxicity during the UV-treatment procedure was observed for the photolytic mixtures at the highest tested concentration. Moreover, the number of PTPs within the reaction mixture that might be responsible for the toxification of TD during UV-treatment was successfully narrowed down by correlating the formation kinetics of PTPs with QSAR predictions and experimental toxicity data. Beyond that, further analysis of the commercially available PTP phthalimide indicated that transformation of TD into phthalimide was not the cause for the toxification of TD during UV-treatment. These results provide a path for toxicological assessment of complex chemical mixtures and in detail show the toxic potential of TD and its PTPs as well as its HTPs. This deserves further attention as UV irradiation might not always be a green technology, because it might pose a toxicological risk for the environment in general and specifically for water compartments. Copyright © 2013 Elsevier Ltd. All rights reserved.
Mutagenicity studies in a tyre plant: in-vitro activity of urine concentrates and rubber chemicals.

PubMed

Crebelli, R; Falcone, E; Aquilina, G; Carere, A; Paoletti, A; Fabri, G

1984-01-01

A possible occupational contribution to urinary mutagenicity was studied in a tyre plant, by assaying concentrates of urine from 72 workmen and 23 controls for their activity in the Ames test and microtitre fluctuation test. The results show that smoking habits but not occupation are related to the appearance of a detectable urinary mutagenicity in strain TA98. A possible synergistic effect of occupation was, however, observed among tyre builders who were smokers. Mutagenicity screening of 25 rubber chemicals, of major technological relevance and used in high volume in the workplace investigated, showed that three of them are weakly active in TA98 and TA100 (tetramethylthiuram disulfide) or TA98 alone (poly-p-dinitrosobenzene and mixed diaryl-p-phenylendiamines).

Induction of micronuclei by HTLV-I Tax: a cellular assay for function.

PubMed

Majone, F; Semmes, O J; Jeang, K T

1993-03-01

Cellular chromosomal damage is ubiquitously seen in HTLV-I-transformed lymphocytes. It is also characteristic of cells that have been exposed to mutagens. A sensitive measurement for mutagen-induced DNA damage is the formation of micronuclei in treated cells. Because current evidence suggests that HTLV-I Tax is etiologically linked to transformation, we tested for its activity in inducing micronuclei. We show here that transfection into cells of a Tax-producing plasmid rapidly induced the formation of micronuclei. This effect cooperated with that of a mutagen (mitomycin C) and was correlated with the inherent trans-activation capacity of Tax. These findings suggest that a commonly used mutagen assay could be a quick biological test for putatively oncogenic proteins.
Genotoxicity profile of fexinidazole--a drug candidate in clinical development for human African trypanomiasis (sleeping sickness).

PubMed

Tweats, David; Bourdin Trunz, Bernadette; Torreele, Els

2012-09-01

The parasitic disease human African trypanomiasis (HAT), also known as sleeping sickness, is a highly neglected fatal condition endemic in sub-Saharan Africa, which is poorly treated with medicines that are toxic, no longer effective or very difficult to administer. New, safe, effective and easy-to-use treatments are urgently needed. Many nitroimidazoles possess antibacterial and antiprotozoal activity and examples such as tinidazole are used to treat trichomoniasis and guardiasis, but concerns about toxicity including genotoxicity limit their usefulness. Fexinidazole, a 2-substituted 5-nitroimidazole rediscovered by the Drugs for Neglected Diseases initiative (DNDi) after extensive compound mining of public and pharmaceutical company databases, has the potential to become a short-course, safe and effective oral treatment, curing both acute and chronic HAT. This paper describes the genotoxicity profile of fexinidazole and its two active metabolites, the sulfoxide and sulfone derivatives. All the three compounds are mutagenic in the Salmonella/Ames test; however, mutagenicity is either attenuated or lost in Ames Salmonella strains that lack one or more nitroreductase(s). It is known that these enzymes can nitroreduce compounds with low redox potentials, whereas their mammalian cell counterparts cannot, under normal conditions. Fexinidazole and its metabolites have low redox potentials and all mammalian cell assays to detect genetic toxicity, conducted for this study either in vitro (micronucleus test in human lymphocytes) or in vivo (ex vivo unscheduled DNA synthesis in rats; bone marrow micronucleus test in mice), were negative. Thus, fexinidazole does not pose a genotoxic hazard to patients and represents a promising drug candidate for HAT. Fexinidazole is expected to enter Phase II clinical trials in 2012.
The Profile of Creativity and Proposing Statistical Problem Quality Level Reviewed From Cognitive Style

NASA Astrophysics Data System (ADS)

Awi; Ahmar, A. S.; Rahman, A.; Minggi, I.; Mulbar, U.; Asdar; Ruslan; Upu, H.; Alimuddin; Hamda; Rosidah; Sutamrin; Tiro, M. A.; Rusli

2018-01-01

This research aims to reveal the profile about the level of creativity and the ability to propose statistical problem of students at Mathematics Education 2014 Batch in the State University of Makassar in terms of their cognitive style. This research uses explorative qualitative method by giving meta-cognitive scaffolding at the time of research. The hypothesis of research is that students who have field independent (FI) cognitive style in statistics problem posing from the provided information already able to propose the statistical problem that can be solved and create new data and the problem is already been included as a high quality statistical problem, while students who have dependent cognitive field (FD) commonly are still limited in statistics problem posing that can be finished and do not load new data and the problem is included as medium quality statistical problem.
In vivo formation of mutagens by intraperitoneal administration of polycyclic aromatic hydrocarbons in animals during exposure to nitrogen dioxide.

PubMed

Miyanishi, K; Kinouchi, T; Kataoka, K; Kanoh, T; Ohnishi, Y

1996-07-01

Consumption of fossil fuels has increased indoor and outdoor concentrations of polycyclic aromatic hydrocarbons (PAHs) and nitrogen dioxide (NO2). To study the combined effect of PAH administration and NO2 exposure on mutagenicity of urine from animals we injected 400 mg/kg body wt i.p. one of five kinds of PAH (pyrene, fluoranthene, fluorene, anthracene and chrysene) into ICR mice, Wistar rats, Syrian golden hamsters or Hartley guinea pigs after exposure to 20 p.p.m. NO2 gas for 24 h and then exposed the animals to NO2 gas for an additional 24 h. During the latter 24 h we collected the urine and assayed its mutagenicity with the Ames Salmonella strains after treatment with beta-glucuronidase and arylsulfatase and extraction with dichloromethane. The urine from mice treated with both PAH and NO2 showed high mutagenicity for Salmonella typhimurium strains TA98 and TA100, whereas the urine from mice treated with PAH and air showed almost no mutagenic activity. The mutagenicity was decreased in nitroreductase- and acetyltransferase-deficient strains TA98NR and TA98/1,8-DNP6 respectively. Treatment with a mixture of 20% of each of the five kinds of PAH and NO2 augmented the urinary mutagenicity of mice 1.5-fold. The urine from hamsters treated with pyrene or fluoranthene and NO2 was also highly mutagenic, but that from rats or guinea pigs was not very mutagenic. The mutagenicity was also decreased in strains TA98NR and TA98/1,8-DNP6. These results suggest that the urine contains nitro compounds and that the nitration of PAHs occurs in the body of animals under exposure to NO2 gas. Actually, the nitrated metabolites of pyrene, 1-nitro-6/8-hydroxypyrene and 1-nitro-3-hydroxypyrene, were detected in the urine from mice treated with pyrene under exposure to NO2 gas. To elucidate the mechanism of in vivo nitration, NO2 (20 p.p.m.) was bubbled through 50 mM Tris-HCl buffer (pH 7.4) or dichloromethane solution containing pyrene or 1-hydroxypyrene (10 microg/ml). Pyrene was not nitrated by NO2 in either aqueous or organic solutions. However, 1-hydroxypyrene was changed to nitrohydroxypyrenes by NO2 in the Tris-HCl buffer, but not in the organic solution. Ascorbic acid, alpha-tocopherol, glutathione oleic acid and hemoglobin were found to inhibit the nitration of 1-hydroxypyrene in aqueous solution. The urinary mutagenicity of mice treated with both pyrene and NO2 was also decreased by oral administration of ascorbic acid and alpha-tocopherol. These results suggest that 1-hydroxypyrene is nitrated by an ionic reaction in the animal body after hydroxylation of pyrene in the liver.
Antimutagens as cancer chemopreventive agents in the diet.

PubMed

Ferguson, L R

1994-05-01

It has been suggested that the use of antimutagens and anticarcinogens in everyday life will be the most effective procedure for preventing human cancer and genetic disease. There are several ways in which mutagenesis can be reduced or prevented. Chemicals which act to interfere with DNA repair or with mutagen metabolism can be effective antimutagens: however such compounds may also increase the probability of mutations by different chemicals or at different sites. In contrast, mutagen scavengers may be less prone to increase mutations by other chemicals. Selected examples illustrate that antimutagenic effects are often specific to certain classes of mutagen and/or certain test systems. Thus, if antimutagens are to have any impact on human disease, it is essential that they are specifically directed against the most common mutagens in daily life. On our current understanding, these are quite diverse in nature, so that combinations of antimutagens will probably be necessary. Two groups of mutagen scavengers (porphyrins and some types of dietary fibre) show some selectivity for large planar and hydrophobic types of carcinogen, which appear to be common in a normal Western diet. Increasing consumption of vitamins C and E, either through increased consumption of fruit and vegetables or through dietary supplementation might reduce formation of N-nitroso compounds, another common class of mutagens. Similarly, carotenoids and related compounds, already present at high quantities in some fruits and vegetables, have excellent antioxidant properties and should be able to counteract effects of endogenous metabolism and other events which generate oxidising species and free radicals. Still other types of antimutagen might be necessary to act against smaller non-planar carcinogens, but there is some question as to the importance of this type of carcinogen in a normal Western diet. It may be necessary to adjust the selection of antimutagens for different population groups, or as our understanding of mutagens in the diet develops further. Current assays for cancer chemoprevention in animals are unlikely to detect some important types of antimutagens, such as mutagen scavengers. A structured testing strategy is suggested, progressing from in vitro to in vivo antimutagenicity tests against a selected range of mutagens. Optimal use of antimutagens might be as a dietary supplement, additional to practical advice on increasing consumption of fruit and vegetables.
Diet-induced obesity increases the frequency of Pig-a mutant erythrocytes in male C57BL/6J mice.

PubMed

Wickliffe, Jeffrey K; Dertinger, Stephen D; Torous, Dorothea K; Avlasevich, Svetlana L; Simon-Friedt, Bridget R; Wilson, Mark J

2016-12-01

Obesity increases the risk of a number of chronic diseases in humans including several cancers. Biological mechanisms responsible for such increased risks are not well understood at present. Increases in systemic inflammation and oxidative stress, endogenous production of mutagenic metabolites, altered signaling in proliferative pathways, and increased sensitivity to exogenous mutagens and carcinogens are some of the potential contributing factors. We hypothesize that obesity creates an endogenously mutagenic environment in addition to increasing the sensitivity to environmental mutagens. To test this hypothesis, we examined two in vivo genotoxicity endpoints. Pig-a mutant frequencies and micronucleus frequencies were determined in blood cells in two independent experiments in 30-week old male mice reared on either a high-fat diet (60% calories from fat) that exhibit an obese phenotype or a normal-fat diet (10% calories from fat) that do not exhibit an obese phenotype. Mice were assayed again at 52 weeks of age in one of the experiments. N-ethyl-N-nitrosourea (ENU) was used as a positive mutation control in one experiment. ENU induced a robust Pig-a mutant and micronucleus response in both phenotypes. Obese, otherwise untreated mice, did not differ from non-obese mice with respect to Pig-a mutant frequencies in reticulocytes or micronucleus frequencies. However, such mice, had significantly higher and sustained Pig-a mutant frequencies (increased 2.5-3.7-fold, p < 0.02) in erythrocytes as compared to non-obese mice (based on measurements collected at 30 weeks or 30 and 52 weeks of age). This suggests that obesity, in the absence of exposure to an exogenous mutagen, is itself mutagenic. Environ. Mol. Mutagen. 57:668-677, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Mutagenicity evaluation of forty-one metal salts by the umu test.

PubMed

Yamamoto, Akiko; Kohyama, Yuko; Hanawa, Takao

2002-01-01

Metallic biomaterials implanted in a human body may corrode and wear, releasing metal ions and debris which may induce adverse reactions such as inflammation, allergy, neoplastic formation, developmental malformation, etc. Mutagenicity is a very fundamental and important toxicity related to carcinogenicity and reproductive/developmental toxicity because the damages to genes or DNA can be a cause of carcinogenesis and developmental abnormalities. However, available mutagenic data on metallic ions and compounds are restricted to the number of elements. Therefore, to obtain the systematic data necessary for metal ion mutagenicity, 41 metal salts encompassing 36 metals and 5 metallic elements tested with different valences, were evaluated on their mutagenicity by a microbial test, the umu test. As a result, K(2)Cr(2)O(7), RhCl(3), IrCl(4), and MgCl(2) are positive without metabolic activation. Concentrations having the maximum mutagenic effect (C(max)) are 9.65 x 10(-5), 1.00 x 10(-4), 3.11 x 10(-3), 4.12 x 10(-3) mol. L(-1), respectively. CuCl(2), VCl(3), CuCl, RhCl(3), K(2)Cr(2)O(7), and IrCl(4) are positive with metabolic activation by S-9 mix with C(max) of 1.60 x 10(-5), 3.91 x 10(-5), 1.57 x 10(-4), 2.00 x 10(-4), 3.86 x 10(-4), 1.56 x 10(-2) mol. L(-1), respectively. Thirty-five metal salts were negative for tests performed both with and without metabolic activation, whereas it was impossible to evaluate the mutagenicity of MoCl(5) and ZrCl(4) by the umu test because of their colorimetric reaction to testing reagents. Copyright 2001 John Wiley & Sons, Inc.
What’s in the Pool? A Comprehensive Identification of Disinfection By-products and Assessment of Mutagenicity of Chlorinated and Brominated Swimming Pool Water

PubMed Central

Richardson, Susan D.; DeMarini, David M.; Kogevinas, Manolis; Fernandez, Pilar; Marco, Esther; Lourencetti, Carolina; Ballesté, Clara; Heederik, Dick; Meliefste, Kees; McKague, A. Bruce; Marcos, Ricard; Font-Ribera, Laia; Grimalt, Joan O.; Villanueva, Cristina M.

2010-01-01

Background Swimming pool disinfectants and disinfection by-products (DBPs) have been linked to human health effects, including asthma and bladder cancer, but no studies have provided a comprehensive identification of DBPs in the water and related that to mutagenicity. Objectives We performed a comprehensive identification of DBPs and disinfectant species in waters from public swimming pools in Barcelona, Catalonia, Spain, that disinfect with either chlorine or bromine and we determined the mutagenicity of the waters to compare with the analytical results. Methods We used gas chromatography/mass spectrometry (GC/MS) to measure trihalomethanes in water, GC with electron capture detection for air, low- and high-resolution GC/MS to comprehensively identify DBPs, photometry to measure disinfectant species (free chlorine, monochloroamine, dichloramine, and trichloramine) in the waters, and an ion chromatography method to measure trichloramine in air. We assessed mutagenicity with the Salmonella mutagenicity assay. Results We identified > 100 DBPs, including many nitrogen-containing DBPs that were likely formed from nitrogen-containing precursors from human inputs, such as urine, sweat, and skin cells. Many DBPs were new and have not been reported previously in either swimming pool or drinking waters. Bromoform levels were greater in brominated than in chlorinated pool waters, but we also identified many brominated DBPs in the chlorinated waters. The pool waters were mutagenic at levels similar to that of drinking water (~ 1,200 revertants/L-equivalents in strain TA100–S9 mix). Conclusions This study identified many new DBPs not identified previously in swimming pool or drinking water and found that swimming pool waters are as mutagenic as typical drinking waters. PMID:20833605
Mutagenic effect of freezing on mitochondrial DNA of Saccharomyces cerevisiae.

PubMed

Stoycheva, T; Venkov, P; Tsvetkov, Ts

2007-06-01

Although suggested in some studies, the mutagenic effect of freezing has not been proved by induction and isolation of mutants. Using a well-defined genetic model, we supply in this communication evidence for the mutagenic effect of freezing on mitochondrial DNA (mtDNA) of the yeast Saccharomyces cerevisiae. The cooling for 2 h at +4 degrees C, followed by freezing for 1 h at -10 degrees C and 16 h at -20 degrees C resulted in induction of respiratory mutations. The immediate freezing in liquid nitrogen was without mutagenic effect. The study of the stepwise procedure showed that the induction of respiratory mutants takes place during the freezing at -10 and -20 degrees C of cells pre-cooled at +4 degrees C. The genetic crosses of freeze-induced mutants evidenced their mitochondrial rho- origin. The freeze-induced rho- mutants are most likely free of simultaneous nuclear mutations. The extracellular presence of cryoprotectants did not prevent the mutagenic effect of freezing while accumulation of cryoprotectors inside cells completely escaped mtDNA from cryodamage. Although the results obtained favor the notion that the mutagenic effect of freezing on yeast mtDNA is due to formation and growth of intracellular ice crystals, other reasons, such as impairment of mtDNA replication or elevated levels of ROS production are discussed as possible explanations of the mutagenic effect of freezing. It is concluded that: (i) freezing can be used as a method for isolation of mitochondrial mutants in S. cerevisiae and (ii) given the substantial development in cryopreservation of cells and tissues, special precautions should be made to avoid mtDNA damage during the cryopreservation procedures.
The 10th anniversary of the publication of genes and environment: memoir of establishing the Japanese environmental mutagen society and a proposal for a new collaborative study on mutagenic hormesis.

PubMed

Sutou, Shizuyo

2017-01-01

The Japanese Environmental Mutagen Society (JEMS) was established in 1972 by 147 members, 11 of whom are still on the active list as of May 1, 2016. As one of them, I introduce some historic topics here. These include 1) establishment of JEMS, 2) the issue of 2-(2-furyl)-3-(3-nitro-2-furyl)acrylamide (AF-2), 3) the Mammalian Mutagenicity Study Group (MMS) and its achievements, and 4) the Collaborative Study Group of the Micronucleus Test (CSGMT) and its achievements. In addition to these historic matters, some of which are still ongoing, a new collaborative study is proposed on adaptive response or hormesis by mutagens. There is a close relationship between mutagens and carcinogens, the dose-response relationship of which has been thought to follow the linear no-threshold model (LNT). LNT was fabricated on the basis of Drosophila sperm experiments using high dose radiation delivered in a short period. The fallacious 60 years-old LNT is applied to cancer induction by radiation without solid data and then to cancer induction by carcinogens also without solid data. Therefore, even the smallest amount of carcinogens is postulated to be carcinogenic without thresholds now. Radiation hormesis is observed in a large variety of living organisms; radiation is beneficial at low doses, but hazardous at high doses. There is a threshold at the boundary between benefit and hazard. Hormesis denies LNT. Not a few papers report existence of chemical hormesis. If mutagens and carcinogens show hormesis, the linear dose-response relationship in mutagenesis and carcinogenesis is denied and thresholds can be introduced.
Microbial mutagenic effects of the DNA minor groove binder pibenzimol (Hoechst 33258) and a series of mustard analogues.

PubMed

Ferguson, L R; Denny, W A

1995-06-01

A series of aniline mustards and half-mustards targeted to DNA by linkage (through a polymethylene chain) to the bisbenzimidazole chromophore of pibenzimol (Hoechst 33258) have been evaluated for their mutagenic properties, as estimated in three strains of Salmonella typhimurium, and for their mitotic crossing-over and petite mutagenesis activities in Saccharomyces cerevisiae strain D5. Agarose gel electrophoresis studies showed that only the derivative with the longest linker chain cross-linked DNA, with the remaining compounds being monoalkylators. The parent (non-alkylator) minor groove binding ligand (Hoechst 33258) was inactive in the bacterial strains TA98 or TA100 but weakly mutagenic in TA102, and caused neither mitotic crossing-over nor 'petite' mutagenesis in yeast. Aniline half-mustard itself (monoalkylator) was an effective base-pair substitution mutagen (events in S. typhimurium strain TA100) with some frameshift mutagenesis activity in TA98, but showed only weak effects in the yeast assays, whereas aniline mustard (cross-linker) was inactive in these bacterial systems but caused substantial amounts of mitotic crossing-over in yeast. The composite molecules studied here showed effects more characteristic of the minor groove binding chromophore than of alkylating moieties. All showed weak mutagenic activity in TA102 and none in TA98. The only compound to show significant mitotic crossing-over ability was the long-chain derivative which cross-linked DNA. For most of the compounds, the mutagenicity data provided no supportive evidence for DNA alkylation. Since other evidence suggests this does occur readily, it is likely to have a different target to that seen with untargeted aniline mustards. The significant antitumor activity and low mutagenic potential shown by these compounds make them worthy of further study.
Polar extracts from (Tunisian) Acacia salicina Lindl. Study of the antimicrobial and antigenotoxic activities

PubMed Central

2012-01-01

Background Methanolic, aqueous and Total Oligomer Flavonoids (TOF)-enriched extracts obtained from the leaves of Acacia salicina 'Lindl.' were investigated for antibacterial, antimutagenic and antioxidant activities. Methods The antimicrobial activity was tested on the Gram positive and Gram negative reference bacterial strains. The Mutagenic and antimutagenic activities against direct acting mutagens, methylmethane sulfonate (MMS) and 4-nitro-o-phenylenediamine (NOPD), and indirect acting mutagens, 2-aminoanthracene (2-AA) and benzo[a]pyrene (B(a)P) were performed with S. typhimurium TA102 and TA98 assay systems. In addition, the enzymatic and nonenzymatic methods were employed to evaluate the anti-oxidative effects of the tested extracts. Results A significant effect against the Gram positive and Gram negative reference bacterial strains was observed with all the extracts. The mutagenic and antimutagenic studies revealed that all the extracts decreased the mutagenicity induced by B(a)P (7.5 μg/plate), 2-AA (5 μg/plate), MMS (1.3 mg/plate) and NOPD (10 μg/plate). Likewise, all the extracts showed an important free radical scavenging activity towards the superoxide anion generated by the xanthine/xanthine oxidase assay system, as well as high Trolox Equivalent Antioxidant Capacity (TEAC), against the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS)+• radical. TOF-enriched extract exhibited the highest protective effect against free radicals, direct acting-mutagen and metabolically activated S9-dependent mutagens. Conclusions The present study indicates that the extracts from A. salicina leaves are a significant source of compounds with the antimutagenic and antioxidant activities, and this may be useful for developing potential chemopreventive substances. PMID:22490278
Bioassay-directed fractionation and salmonella mutagenicity of automobile and forklift diesel exhaust particles.

PubMed Central

DeMarini, David M; Brooks, Lance R; Warren, Sarah H; Kobayashi, Takahiro; Gilmour, M Ian; Singh, Pramila

2004-01-01

Many pulmonary toxicity studies of diesel exhaust particles (DEPs) have used an automobile-generated sample (A-DEPs) whose mutagenicity has not been reported. In contrast, many mutagenicity studies of DEPs have used a forklift-generated sample (SRM 2975) that has been evaluated in only a few pulmonary toxicity studies. Therefore, we evaluated the mutagenicity of both DEPs in Salmonella coupled to a bioassay-directed fractionation. The percentage of extractable organic material (EOM) was 26.3% for A-DEPs and 2% for SRM 2975. Most of the A-EOM (~55%) eluted in the hexane fraction, reflecting the presence of alkanes and alkenes, typical of uncombusted fuel. In contrast, most of the SRM 2975 EOM (~58%) eluted in the polar methanol fraction, indicative of oxygenated and/or nitrated organics derived from combustion. Most of the direct-acting, base-substitution activity of the A-EOM eluted in the hexane/dichloromethane (DCM) fraction, but this activity eluted in the polar methanol fraction for the SRM 2975 EOM. The direct-acting frameshift mutagenicity eluted across fractions of A-EOM, whereas > 80% eluted only in the DCM fraction of SRM 2975 EOM. The A-DEPs were more mutagenic than SRM 2975 per mass of particle, having 227 times more polycyclic aromatic hydrocarbon-type and 8-45 more nitroarene-type mutagenic activity. These differences were associated with the different conditions under which the two DEP samples were generated and collected. A comprehensive understanding of the mechanisms responsible for the health effects of DEPs requires the evaluation of DEP standards for a variety of end points, and our results highlight the need for multidisciplinary studies on a variety of representative samples of DEPs. PMID:15175166
Identification of formaldehyde as the metabolite responsible for the mutagenicity of methyl tertiary-butyl ether in the activated mouse lymphoma assay.

PubMed

Mackerer, C R; Angelosanto, F A; Blackburn, G R; Schreiner, C A

1996-09-01

Methyl tertiary-butyl ether (MTBE), which is added to gasoline as an octane enhancer and to reduce automotive emissions, has been evaluated in numerous toxicological tests, including those for genotoxicity. MTBE did not show any mutagenic potential in the Ames bacterial assay or any clastogenicity in cytogenetic tests. However, it has been shown to be mutagenic in an in vitro gene mutation assay using mouse lymphoma cells when tested in the presence, but not in the absence, of a rat liver-derived metabolic activation system (S-9). In the present study, MTBE was tested to determine if formaldehyde, in the presence of the S-9, was responsible for the observed mutagenicity. A modification of the mouse lymphoma assay was employed which permits determination of whether a suspect material is mutagenic because it contains or is metabolized to formaldehyde. In the modified assay, the enzyme formaldehyde dehydrogenase (FDH) and its co-factor, NAD+ are added in large excess during the exposure period so that any formaldehyde produced in the system is rapidly converted to formic acid which is not genotoxic. An MTBE dose-responsive increase in the frequency of mutants and in cytotoxicity occurred without FDH present, and this effect was greatly reduced in the presence of FDH NAD+. The findings clearly demonstrate that formaldehyde derived from MTBE is responsible for mutagenicity of MTBE in the activated mouse lymphoma assay. Furthermore, the results suggest that the lack of mutagenicity/clastogenicity seen with MTBE in other in vitro assays might have resulted from inadequacies in the test systems employed for those assays.
Mutagenicity of comfrey (Symphytum Officinale) in rat liver

PubMed Central

Mei, N; Guo, L; Fu, P P; Heflich, R H; Chen, T

2005-01-01

Comfrey is a rat liver toxin and carcinogen that has been used as a vegetable and herbal remedy by humans. In order to evaluate the mechanisms underlying its carcinogenicity, we examined the mutagenicity of comfrey in the transgenic Big Blue rat model. Our results indicate that comfrey is mutagenic in rat liver and the types of mutations induced by comfrey suggest that its tumorigenicity results from the genotoxicity of pyrrolizidine alkaloids in the plant. PMID:15726100
Physicochemical characteristics, mutagenicity and genotoxicity of airborne particles under industrial and rural influences in Northern Lebanon.

PubMed

Melki, Pamela N; Ledoux, Frédéric; Aouad, Samer; Billet, Sylvain; El Khoury, Bilal; Landkocz, Yann; Abdel-Massih, Roula M; Courcot, Dominique

2017-08-01

In this work, the main objectives were to assess the mutagenic and genotoxic effects of fine particulate matter collected in an industrial influenced site in comparison with a non-industrial influenced one (rural site) and to relate the particulate matter (PM) composition to the observed genotoxic effects. At the industrial influenced site, higher concentrations of phosphates, trace metals, and polycyclic aromatic hydrocarbons (PAHs) in particles could be related to the contributions of quarries, fertilizer producer, cement plants, and tires burning. Gasoline and diesel combustion contributions were evidenced in particles collected at both sites. Particles collected under industrial influence showed a higher mutagenic potential on three tested strains of Salmonella typhimurium (TA98, YG1041, and TA102), and especially on the YG1041, compared to particles from the rural site. Furthermore, only particles collected in the vicinity of the industrial site showed a tendency to activate the SOS responses in Escherichia coli PQ37, which is indicative of DNA damage as a result of exposure of the bacteria cells to the action of mutagenic samples. The mutagenicity and genotoxicity of the industrial PM 2.5-0.3 particulates may be attributed to its composition especially in organic compounds. This study showed that proximity of industries can affect local PM composition as well as PM genotoxic and mutagenic potential.
Cooking with Fire: The Mutagenicity- and PAH-Emission ...

EPA Pesticide Factsheets

Emissions from solid fuels used for cooking cause ~4 million premature deaths per year. Advanced solid-fuel cookstoves are a potential solution, but they should be assessed by appropriate performance indicators, including biological effects. We evaluated two categories of solid-fuel cookstoves for 8 pollutant- and 4 mutagenicity-emission factors, correlated the mutagenicity-emission factors, and compared them to those of other combustion emissions. We burned red oak in a 3-stone fire (TSF), a natural-draft stove (NDS), and a forced-draft stove (FDS); we combusted propane as a liquified petroleum gas control fuel. We determined emission factors based on useful energy (megajoules delivered, MJd) for carbon monoxide, nitrogen oxides (NOx), black carbon, methane, total hydrocarbons, 32 polycyclic aromatic hydrocarbons, PM2.5, levoglucosan (a wood-smoke marker), and mutagenicity in Salmonella. Other than NOx the emission factors per MJd correlated highly among each other (r2 ≥ 0.92); NOx correlated 0.58-0.76 with the other emission factors. Excluding NOx, the NDS and FDS reduced the emission factors on average 68 and 92%, respectively, relative to the TSF. Nonetheless, the mutagenicity-emission factor based on fuel energy used (MJthermal) for the most efficient stove (FDS) was intermediate to that of a large diesel bus engine and a small diesel generator. Both mutagenicity- and pollutant-emission factors may be informative for characterizing cookstove
Mutagenicity studies in a tyre plant: in vitro activity of workers' urinary concentrates and raw materials.

PubMed

Crebelli, R; Paoletti, A; Falcone, E; Aquilina, G; Fabri, G; Carere, A

1985-07-01

The possible contribution to urinary mutagenicity of occupational exposures in the rubber industry was studied by assaying the urine concentrates of 72 workmen (44 smokers) employed in a tyre plant. Twenty three clerks (16 smokers) engaged in the administrative department of the same factory served as presumptive unexposed controls. XAD-2 resin concentrates of urine samples were assayed in the plate incorporation test and in the microtitre fluctuation assay with Salmonella typhimurium strains TA1535, TA98, and TA100. Furthermore, the in vitro mutagenicity of the major raw materials in use at the plant was determined in the plate incorporation assay with S typhimurium strains TA1535, TA1537, TA98, and TA100. The results obtained from the urinary mutagenicity study show that smoking habits, but not occupation, were statistically significantly related to the appearance of a urinary mutagenicity that was detectable with strain TA98. A possible synergistic effect of occupation with smoking was observed among tyre builders who were also smokers. The study of the raw materials showed that three technical grade materials were weakly active as mutagens in strain TA98 in the absence (poly-p-dinitrosobenzene) or in the presence of metabolic activation (mixed diaryl-p-phenylendiamines and tetramethyltiuram disulphide). The latter chemical was also weakly active in strain TA100.
Mutagenicity studies in a tyre plant: in vitro activity of workers' urinary concentrates and raw materials.

PubMed Central

Crebelli, R; Paoletti, A; Falcone, E; Aquilina, G; Fabri, G; Carere, A

1985-01-01

The possible contribution to urinary mutagenicity of occupational exposures in the rubber industry was studied by assaying the urine concentrates of 72 workmen (44 smokers) employed in a tyre plant. Twenty three clerks (16 smokers) engaged in the administrative department of the same factory served as presumptive unexposed controls. XAD-2 resin concentrates of urine samples were assayed in the plate incorporation test and in the microtitre fluctuation assay with Salmonella typhimurium strains TA1535, TA98, and TA100. Furthermore, the in vitro mutagenicity of the major raw materials in use at the plant was determined in the plate incorporation assay with S typhimurium strains TA1535, TA1537, TA98, and TA100. The results obtained from the urinary mutagenicity study show that smoking habits, but not occupation, were statistically significantly related to the appearance of a urinary mutagenicity that was detectable with strain TA98. A possible synergistic effect of occupation with smoking was observed among tyre builders who were also smokers. The study of the raw materials showed that three technical grade materials were weakly active as mutagens in strain TA98 in the absence (poly-p-dinitrosobenzene) or in the presence of metabolic activation (mixed diaryl-p-phenylendiamines and tetramethyltiuram disulphide). The latter chemical was also weakly active in strain TA100. PMID:4015996
Di-epoxides of the three isomeric dicyclopenta-fused pyrenes: ultimate mutagenic active agents.

PubMed

Otero-Lobato, María José; Kaats-Richters, Veronica E M; Havenith, Remco W A; Jenneskens, Leonardus W; Seinen, Willem

2004-11-14

To rationalize the high bacterial mutagenic response recently found for the (di-) cyclopenta-fused pyrene congeners, viz. cyclopenta[cd]-(1), dicyclopenta[cd,mn]-(2), dicyclopenta[cd,fg]-(3) and dicyclopenta[cd,jk]pyrene (4), in the presence of a metabolic activation mixture (S9-mix), their (di-)epoxides at the externally fused unsaturated five-membered rings were previously proposed as the ultimate mutagenic active forms. In this study, cyclopenta[cd]pyrene-3,4-epoxide (5) and the novel dicyclopenta[cd,mn]pyrene-1,2,4,5-di-epoxide (6), dicyclopenta[cd,fg]pyrene-5,6,7,8-di-epoxide (7) and dicyclopenta[cd,jk]pyrene-1,2,6,7-di-epoxide (8) were synthesised from 1 to 4, respectively, and subsequently assayed for bacterial mutagenicity in the standard microsomal/histidine reverse mutation assay (Ames-assay with Salmonella typhimurium strain TA98). The di-epoxides 6-8 are present as a mixture of their cis- and trans-stereo-isomers in a close to 1:1 ratio ((1)H NMR spectroscopy and ab initio IGLO/III//RHF/6-31G** calculations). The direct-acting mutagenic activity and the strong cytotoxicity exerted by 5-8 both in the absence or presence of an exogenous metabolic activation system (+/-S9-mix) demonstrate that the ultimate mutagenic active forms are the proposed (di-)epoxides of 1-4.

Sperm shape abnormality and urine mutagenicity in mice treated with niclosamide.

PubMed

Vega, S G; Guzmán, P; García, L; Espinosa, J; Cortinas de Nava, C

1988-02-01

Niclosamide, a widely used anthelmintic drug in underdeveloped countries, is known to be mutagenic in the Salmonella typhimurium microsomal test system. The urine obtained from mice treated with niclosamide is mutagenic in the TA98 and TA1538 strains. Its effects on mouse-sperm morphology were evaluated in CD1 and (BALB/cJ x DBA/2J) F1 mice after 5 daily oral niclosamide doses of either 60, 80, 100 or 120 mg/kg. A statistically significant increase in abnormal sperm morphology was detected in both CD1 and (BALB/cJ x DBA/2J) F1 mice. No drug-related effects on testis weight nor on sperm count were observed in either genotype. Urine samples obtained from niclosamide-treated F1 mice were assayed with the Salmonella typhimurium strain TA1538 both in the absence and presence of beta-glucuronidase. In the absence of glucuronidase, urine mutagenicity increased with increasing dose and the highest doses were toxic. In the presence of glucuronidase, urine mutagenicity and toxicity also increased. Only at the highest dose (120 mg/kg), however, was there a positive correlation between the urine mutagenic activity and an increase in the number of abnormal sperm. The results of this study suggest that the increase in abnormal sperm depends on the systemic presence of non-conjugated niclosamide metabolites.
The effect of green tea and olive oil on the mutagenic activity of heterocyclic amines extracted from common food consumed in Saudi Arabia.

PubMed

Awney, Hala

2011-05-01

The effect of green tea (GT) and green tea with olive oil (GT+OL) as antioxidants on the formation and mutagenic activity of heterocyclic aromatic amines (HCAs) extracted from beef shawerma, grilled chicken and fried beef liver was examined. HCAs were extracted by blue rayon, analyzed as spiked and unspiked samples with high-performance liquid chromatography and its mutagenic response was assessed by Sallmonela typhimurium 100 in the Ames test. Surprisingly, GT and GT+OL augmented HCAs measured in beef shawerma and grilled chicken but total HCAs measured in GT+OL were less than GT treatment. Both treatments altered the HCA profile as imidazoquinoline type became the most abundant. In control and GT+OL fried beef liver no HCAs were detected, but Trp-P1 was detected in GT treatment. Generally, the mutagenic response of HCAs measured in GT+OL was less than GT in beef shawerma and grilled chicken. However, the mutagenic response of control and 2% GT+OL fried liver was negative. These data suggest that GT concentrations used in this study may induce free radical formation during the Millared reaction due to its pro-oxidative effect, which augmented the HCAs formed and its mutagenic response. In order to optimize both safety and quality of our diets, more need to be done to fully understand the risk of HCAs in food.
Characterization and Quantification of Compounds in the Hydroalcoholic Extract of the Leaves from Terminalia catappa Linn. (Combretaceae) and Their Mutagenic Activity

PubMed Central

Mininel, Francisco José; Leonardo Junior, Carlos Sérgio; Espanha, Lívia Greghi; Resende, Flávia Aparecida; Varanda, Eliana Aparecida; Leite, Clarice Queico Fujimura; Vilegas, Wagner; dos Santos, Lourdes Campaner

2014-01-01

Terminalia is a genus of Combretaceous plants widely distributed in tropical and subtropical regions. Thus, the aim of this study was to quantify the majority compounds of the hydroalcoholic extract (7 : 3, v/v) of the leaves from T. catappa by HPLC-PDA, chemically characterize by hyphenated techniques (HPLC-ESI-IT-MSn) and NMR, and evaluate its mutagenic activity by the Salmonella/microsome assay on S. typhimurium strains TA98, TA97a, TA100, and TA102. The quantification of analytes was performed using an external calibration standard. Punicalagin is the most abundant polyphenol found in the leaves. The presence of this compound as a mixture of anomers was confirmed using HPLC-PDA and 1H and 13C NMR. Mutagenic activity was observed in strains TA100 and TA97a. As the extract is a complex mixture of punicalagin, its derivatives, and several other compounds, the observed mutagenicity may be explained in part by possible synergistic interaction between the compounds present in the extract. These studies show that mutagenic activity of T. catappa in the Ames test can only be observed when measured at high concentrations. However, considering the mutagenic effects observed for T. catappa, this plant should be used cautiously for medicinal purposes. PMID:24734110
Mutagenicity and estrogenicity of raw water and drinking water in an industrialized city in the Yangtze River Delta.

PubMed

Xiao, Sanhua; Lv, Xuemin; Zeng, Yifan; Jin, Tao; Luo, Lan; Zhang, Binbin; Zhang, Gang; Wang, Yanhui; Feng, Lin; Zhu, Yuan; Tang, Fei

2017-10-01

Public concern was aroused by frequently reported water pollution incidents in Taihu Lake and the Yangtze River. The pollution also caught and sustained the attention of the scientific community. From 2010 to 2016, raw water and drinking water samples were continually collected at Waterworks A and B (Taihu Lake) and Waterworks C (Yangtze River). The non-volatile organic pollutants in the water samples were extracted by solid phase extraction. Ames tests and yeast estrogen screen (YES) assays were conducted to evaluate the respective mutagenic and estrogenic effects. Water samples from the Yangtze River-based Waterworks C possessed higher mutagenicity than those from Taihu Lake-based Waterworks A (P＜0.001) and Waterworks B (P = 0.026). Water treatment enhanced the direct mutagenicity (P = 0.022), and weakened the estrogenicity of the raw water (P＜0.001) with a median removal rate of 100%. In fact, very few of the finished samples showed estrogenic activity. Raw water samples from Waterworks A showed weaker estrogenicity than those from Waterworks B (P = 0.034) and Waterworks C (P = 0.006). In summary, mutagenic effects in drinking water and estrogenic effects in raw water merited sustained attention. The Yangtze River was more seriously polluted by mutagenic and estrogenic chemicals than Taihu Lake was. Copyright © 2017 Elsevier Ltd. All rights reserved.
Incorporating structure from motion uncertainty into image-based pose estimation

NASA Astrophysics Data System (ADS)

Ludington, Ben T.; Brown, Andrew P.; Sheffler, Michael J.; Taylor, Clark N.; Berardi, Stephen

2015-05-01

A method for generating and utilizing structure from motion (SfM) uncertainty estimates within image-based pose estimation is presented. The method is applied to a class of problems in which SfM algorithms are utilized to form a geo-registered reference model of a particular ground area using imagery gathered during flight by a small unmanned aircraft. The model is then used to form camera pose estimates in near real-time from imagery gathered later. The resulting pose estimates can be utilized by any of the other onboard systems (e.g. as a replacement for GPS data) or downstream exploitation systems, e.g., image-based object trackers. However, many of the consumers of pose estimates require an assessment of the pose accuracy. The method for generating the accuracy assessment is presented. First, the uncertainty in the reference model is estimated. Bundle Adjustment (BA) is utilized for model generation. While the high-level approach for generating a covariance matrix of the BA parameters is straightforward, typical computing hardware is not able to support the required operations due to the scale of the optimization problem within BA. Therefore, a series of sparse matrix operations is utilized to form an exact covariance matrix for only the parameters that are needed at a particular moment. Once the uncertainty in the model has been determined, it is used to augment Perspective-n-Point pose estimation algorithms to improve the pose accuracy and to estimate the resulting pose uncertainty. The implementation of the described method is presented along with results including results gathered from flight test data.
Organic emissions from coal pyrolysis: mutagenic effects.

PubMed Central

Braun, A G; Wornat, M J; Mitra, A; Sarofim, A F

1987-01-01

Four different types of coal have been pyrolyzed in a laminar flow, drop tube furnace in order to establish a relationship between polycyclic aromatic compound (PAC) evolution and mutagenicity. Temperatures of 900K to 1700K and particle residence times up to 0.3 sec were chosen to best simulate conditions of rapid rate pyrolysis in pulverized (44-53 microns) coal combustion. The specific mutagenic activity (i.e., the activity per unit sample weight) of extracts from particulates and volatiles captured on XAD-2 resin varied with coal type according to the order: subbituminous greater than high volatile bituminous greater than lignite greater than anthracite. Total mutagenic activity (the activity per gram of coal pyrolyzed), however, varied with coal type according to the order: high volatile bituminous much greater than subbituminous = lignite much greater than anthracite, due primarily to high organic yield during high volatile bituminous coal pyrolysis. Specific mutagenic activity peaked in a temperature range of 1300K to 1500K and generally appeared at higher temperatures and longer residence times than peak PAC production. PMID:3311724
Cytotoxicity and mutagenicity of fluoxetine hydrochloride (Prozac), with or without vitamins A and C, in plant and animal model systems.

PubMed

Düsman, E; Almeida, I V; Mariucci, R G; Mantovani, M S; Vicentini, V E P

2014-01-28

Fluoxetine, commonly known as Prozac, is the first representative of the so-called new generation of antidepressants that promise efficacy, with few side effects, against deep depression, nervous bulimia, and anxiety. As there is a growing number of people suffering from anxiety and depression; consequently, the use of fluoxetine is also increasing. Verifying absence of drug effects such as cytotoxicity or mutagenicity is of great importance. Certain vitamins, such as vitamin A (retinol, retinoids) and vitamin C (ascorbic acid) protect and are extremely active against mutagens. We evaluated the cytotoxic and mutagenic activity of fluoxetine, with and without concomitant administration of vitamin A or C, in Allium cepa meristem cells and Wistar rat bone marrow cells. The A. cepa meristem cells showed fluoxetine cytotoxicity; concomitant treatment with vitamin A or C proved non-protective. Treatment of Wistar rats with fluoxetine intraperitoneally or via gavage did not affect cell division or cause clastogenic effects. Vitamin A and C did not affect the cytotoxicity or mutagenicity of fluoxetine in the rat cells.
A perspective of Genes and Environment for the development of environmental mutagen research in Asia.

PubMed

Yagi, Takashi

2017-01-01

Two years have passed since the Japanese Environmental Society (JEMS) made the official journal Genes and Environment (G&E) open access. Current subjects on environmental mutagen research to further advance this field are described herein, and the roles of JEMS and G&E are discussed. Various important subjects are being investigated in current research fields such as severe environmental pollution in Asian countries; the identification of new hazardous substances and elucidation of mutation mechanisms using newly developed techniques; the development of new genotoxicity assays including in silico predictions using information technology and artificial intelligence as well as bioassays. International exchange by scientists is important for advancing these research fields through international conferences such as the 12th International Conference and 5th Asian Congress on Environmental Mutagens and the 7th International Workshop on Genotoxicity Testing that will be held in 2017. G&E provides a common platform for high quality environmental mutagen research, contributes to the dissemination of Asian environmental mutagen research, and potentiates the level of research being conducted.
Mutagenicity assessment of airborne particles in Mexico City

NASA Astrophysics Data System (ADS)

Villalobos-Pietrini, Rafael; Blanco, Salvador; Gomez-Arroyo, Sandra

The Ames's TA98 strain of Salmonella typhimurium with and without mammalian metabolic activation was used to detect the mutagenic activity of organic chemicals associated with airborne particles. Two kinds of particles: total suspended (TSP) and those particles with an aerodynamic diameter of 10 μm or smaller (PM 10) were collected in glass fiber filters using high-volume samplers during the dry season (December 1989-March 1990) in the Metropolitan Area of Mexico City at five stations of the air quality network belonging to the Ministry of Social Development. Although the highest mass concentrations of particles were obtained from the Northeastern and Southeastern areas, the largest frequency of mutations was found Downtown which indicated that vehicle exhaust was an important source. Contrary to what was expected, the mutagenic responses were higher for PM10 than for TSP samples. On the other hand, the microsome activation increased significantly the mutagenic activity of the complex mixture, which hinted at the presence of higher amounts of indirect (or promutagens) than direct mutagens both for TSP and PM10.
Mutagenicity and genotoxicity studies of aspartame.

PubMed

Otabe, Akira; Ohta, Fumio; Takumi, Asuka; Lynch, Barry

2018-02-08

Two studies were conducted to further assess its mutagenic and genotoxic potential. In a bacterial reverse mutation pre-incubation study, Salmonella typhimurium strains TA100, TA1535, TA98, and TA1537 and Escherichia coli WP2 uvrA were treated with aspartame at concentrations of up to 5000 μg/plate with or without metabolic activation and showed no mutagenic potential. Similarly, in vivo micronucleus testing of aspartame following gavage administration (500-2000 mg/kg body weight) to Crlj:CD1(ICR) strain SPF male mice showed no increase in the proportion of micronucleated polychromatic erythrocytes in bone marrow cells collected and evaluated 24 or 48 h post administration. Overall, aspartame had no potential for mutagenic or genotoxic activity. Copyright © 2018 Elsevier Inc. All rights reserved.
Determination of mutagenicity of the precipitate formed by sodium hypochlorite and chlorhexidine using the Ames test.

PubMed

Patil, Pranali; Aminoshariae, Anita; Harding, Jarrod; Montagnese, Thomas A; Mickel, Andre

2016-04-01

The aim of this study was to determine the direct mutagenic potential of any precipitate formed by combining sodium hypochlorite (NaOCl) and chlorhexidine (CHX). The precipitates formed by NaOCl and CHX were dissolved in 100% dimethyl sulfoxide and cultured with mutant Salmonella Typhimurium strains. The cells were observed for reverse mutation. The numbers of positive/mutated wells were statistically compared with those in the background plates using the two-sample proportion independent t-test. The precipitates were not found to be significantly more mutagenic than the background plates. Within the limitations of this study, the results suggest that the precipitates formed when sodium hypochlorite and chlorhexidine contact did not show mutagenic (and are therefore carcinogenic) potential. © 2015 Australian Society of Endodontology.
Monitoring genotoxic exposure in uranium mines.

PubMed Central

Srám, R J; Dobiás, L; Rössner, P; Veselá, D; Veselý, D; Rakusová, R; Rericha, V

1993-01-01

Recent data from deep uranium mines in Czechoslovakia indicated that mines are exposed to other mutagenic factors in addition to radon daughter products. Mycotoxins were identified as a possible source of mutagens in these mines. Mycotoxins were examined in 38 samples from mines and in throat swabs taken from 116 miners and 78 controls. The following mycotoxins were identified from mines samples: aflatoxins B1 and G1, citrinin, citreoviridin, mycophenolic acid, and sterigmatocystin. Some mold strains isolated from mines and throat swabs were investigated for mutagenic activity by the SOS chromotest and Salmonella assay with strains TA100 and TA98. Mutagenicity was observed, especially with metabolic activation in vitro. These data suggest that mycotoxins produced by molds in uranium mines are a new genotoxic factor for uranium miners. PMID:8143610
Antimutagenic effects of betel leaf extract against the mutagenicity of two tobacco-specific N-nitrosamines.

PubMed

Padma, P R; Amonkar, A J; Bhide, S V

1989-03-01

Epidemiological studies have implicated chewing tobacco alone to be more hazardous than chewing tobacco with betel quid. Experimental studies have shown that betel leaf is antimutagenic against standard mutagens like benzo[a]pyrene and dimethylbenz[a]anthracene. Since the tobacco-specific N-nitrosamines (TSNA) are the only carcinogens present in unburnt forms of tobacco, including chewing tobacco, we tested the effect of an extract of betel leaf against the mutagenicity of the two important TSNA, viz., N'-nitrosonornicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, using the Ames Salmonella/microsome assay with TA100 +S9 and the in vivo micronucleus test. In both the test systems it was observed that betel leaf extract suppressed the mutagenic effects of both the nitrosamines to a significant extent.
Face pose tracking using the four-point algorithm

NASA Astrophysics Data System (ADS)

Fung, Ho Yin; Wong, Kin Hong; Yu, Ying Kin; Tsui, Kwan Pang; Kam, Ho Chuen

2017-06-01

In this paper, we have developed an algorithm to track the pose of a human face robustly and efficiently. Face pose estimation is very useful in many applications such as building virtual reality systems and creating an alternative input method for the disabled. Firstly, we have modified a face detection toolbox called DLib for the detection of a face in front of a camera. The detected face features are passed to a pose estimation method, known as the four-point algorithm, for pose computation. The theory applied and the technical problems encountered during system development are discussed in the paper. It is demonstrated that the system is able to track the pose of a face in real time using a consumer grade laptop computer.
The photo-oxidation of automobile emissions: measurements of the transformation products and their mutagenic activity

NASA Astrophysics Data System (ADS)

Kleindienst, Tadeusz E.; Smith, David F.; Hudgens, Edward E.; Snow, Richard F.; Perry, Erica; Claxton, Larry D.; Bufalini, Joseph J.; Black, Francis M.; Cupitt, Larry T.

Dilute mixtures of automobile emissions (comprising 50% exhaust and 50% surrogate evaporative emissions) were irradiated in a 22.7 m 3 smog chamber and tested for mutagenic activity by using a variant of the Ames test. The exhaust was taken from a single vehicle, a 1977 Ford Mustang equipped with a catalytic converter. Irradiated and nonirradiated gas-phase emissions were used in exposures of the bacteria, Salmonella typhimurium, strains TA100 and TA98. A single set of vehicular operating conditions was used to perform multiple exposures. The mutagenic activities of extracts from the particulate phase were also measured with the standard plate incorporation assay. (In most experiments only direct-acting mutagenic compounds were measured.) The gas-phase data for TA100 and TA98 showed increased activity for the irradiated emissions when compared to the nonirradiated mixture, which exhibited negligible activity with respect to the control values. The particulate phase for both the irradiated and nonirradiated mixtures showed negligible activity when results were compared to the control values for both strains. However, the experimental conditions limited the amount of extractable mass which could be collected in the particulate phase. The measured activities from the gas phase and particulate phase were converted to the number of revertants per cubic meter of effluent (i.e. the mutagenic density) to compare the contributions of each of these phases to the total mutagenic activity for each strain. Under the experimental conditions of this study, the mutagenic density of the gas-phase component of the irradiated mixture contributed approximately two orders of magnitude more of the total TA100 activity than did the particulate phase. For TA98 the gas-phase component contributed approximately one order of magnitude more. However, caution must be exercised in extrapolating these results to urban atmospheres heavily impacted by automotive emissions, because the bacterial mutagenicity assay was used as a screening method, and additional assays using mammalian systems have not yet been conducted. In addition, only limited number of conditions were able to be tested. The significance and limitations of the results are discussed.
Mutagenicity and Pollutant Emission Factors of Solid-Fuel Cookstoves: Comparison with Other Combustion Sources

PubMed Central

Mutlu, Esra; Warren, Sarah H.; Ebersviller, Seth M.; Kooter, Ingeborg M.; Schmid, Judith E.; Dye, Janice A.; Linak, William P.; Gilmour, M. Ian; Jetter, James J.; Higuchi, Mark; DeMarini, David M.

2016-01-01

Background: Emissions from solid fuels used for cooking cause ~4 million premature deaths per year. Advanced solid-fuel cookstoves are a potential solution, but they should be assessed by appropriate performance indicators, including biological effects. Objective: We evaluated two categories of solid-fuel cookstoves for eight pollutant and four mutagenicity emission factors, correlated the mutagenicity emission factors, and compared them to those of other combustion emissions. Methods: We burned red oak in a 3-stone fire (TSF), a natural-draft stove (NDS), and a forced-draft stove (FDS), and we combusted propane as a liquified petroleum gas control fuel. We determined emission factors based on useful energy (megajoules delivered, MJd) for carbon monoxide, nitrogen oxides (NOx), black carbon, methane, total hydrocarbons, 32 polycyclic aromatic hydrocarbons, PM2.5, levoglucosan (a wood-smoke marker), and mutagenicity in Salmonella. Results: With the exception of NOx, the emission factors per MJd were highly correlated (r ≥ 0.97); the correlation for NOx with the other emission factors was 0.58–0.76. Excluding NOx, the NDS and FDS reduced the emission factors an average of 68 and 92%, respectively, relative to the TSF. Nevertheless, the mutagenicity emission factor based on fuel energy used (MJthermal) for the most efficient stove (FDS) was between those of a large diesel bus engine and a small diesel generator. Conclusions: Both mutagenicity and pollutant emission factors may be informative for characterizing cookstove performance. However, mutagenicity emission factors may be especially useful for characterizing potential health effects and should be evaluated in relation to health outcomes in future research. An FDS operated as intended by the manufacturer is safer than a TSF, but without adequate ventilation, it will still result in poor indoor air quality. Citation: Mutlu E, Warren SH, Ebersviller SM, Kooter IM, Schmid JE, Dye JA, Linak WP, Gilmour MI, Jetter JJ, Higuchi M, DeMarini DM. 2016. Mutagenicity and pollutant emission factors of solid-fuel cookstoves: comparison with other combustion sources. Environ Health Perspect 124:974–982; http://dx.doi.org/10.1289/ehp.1509852 PMID:26895221
Comparative mutagenicity and genotoxicity of particles and aerosols emitted by the combustion of standard vs. rapeseed methyl ester supplemented bio-diesel fuels: impact of after treatment devices: oxidation catalyst and particulate filter.

PubMed

André, V; Barraud, C; Capron, D; Preterre, D; Keravec, V; Vendeville, C; Cazier, F; Pottier, D; Morin, J P; Sichel, F

2015-01-01

Diesel exhausts are partly responsible for the deleterious effects on human health associated with urban pollution, including cardiovascular diseases, asthma, COPD, and possibly lung cancer. Particulate fraction has been incriminated and thus largely investigated for its genotoxic properties, based on exposure conditions that are, however, not relevant for human risk assessment. In this paper, original and more realistic protocols were used to investigate the hazards induced by exhausts emitted by the combustion of standard (DF0) vs. bio-diesel fuels (DF7 and DF30) and to assess the impact of exhaust treatment devices (DOC and DPF). Mutagenicity and genotoxicity were evaluated for (1) resuspended particles ("off line" exposure that takes into account the bioavailability of adsorbed chemicals) and for (2) the whole aerosols (particles+gas phase components) under continuous flow exposure ("on line" exposure). Native particles displayed mutagenic properties associated with nitroaromatic profiles (YG1041), whereas PAHs did not seem to be involved. After DOC treatment, the mutagenicity of particles was fully abolished. In contrast, the level of particle deposition was low under continuous flow exposure, and the observed mutagenicity in TA98 and TA102 was thus attributable to the gas phase. A bactericidal effect was also observed in TA102 after DOC treatment, and a weak but significant mutagenicity persisted after DPF treatment for bio-diesel fuels. No formation of bulky DNA-adducts was observed on A549 cells exposed to diesel exhaust, even in very drastic conditions (organic extracts corresponding to 500 μg equivalent particule/mL, 48 h exposure). Taken together, these data indicate that the exhausts issued from the bio-diesel fuels supplemented with rapseed methyl ester (RME), and generated by current diesel engines equipped with after treatment devices are less mutagenic than older ones. The residual mutagenicity is linked to the gas phase and could be due to pro-oxydants, mainly for RME-supplemented fuels. Copyright © 2014 Elsevier B.V. All rights reserved.
A novel QSAR model of Salmonella mutagenicity and its application in the safety assessment of drug impurities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valencia, Antoni; Prous, Josep; Mora, Oscar

As indicated in ICH M7 draft guidance, in silico predictive tools including statistically-based QSARs and expert analysis may be used as a computational assessment for bacterial mutagenicity for the qualification of impurities in pharmaceuticals. To address this need, we developed and validated a QSAR model to predict Salmonella t. mutagenicity (Ames assay outcome) of pharmaceutical impurities using Prous Institute's Symmetry℠, a new in silico solution for drug discovery and toxicity screening, and the Mold2 molecular descriptor package (FDA/NCTR). Data was sourced from public benchmark databases with known Ames assay mutagenicity outcomes for 7300 chemicals (57% mutagens). Of these data, 90%more » was used to train the model and the remaining 10% was set aside as a holdout set for validation. The model's applicability to drug impurities was tested using a FDA/CDER database of 951 structures, of which 94% were found within the model's applicability domain. The predictive performance of the model is acceptable for supporting regulatory decision-making with 84 ± 1% sensitivity, 81 ± 1% specificity, 83 ± 1% concordance and 79 ± 1% negative predictivity based on internal cross-validation, while the holdout dataset yielded 83% sensitivity, 77% specificity, 80% concordance and 78% negative predictivity. Given the importance of having confidence in negative predictions, an additional external validation of the model was also carried out, using marketed drugs known to be Ames-negative, and obtained 98% coverage and 81% specificity. Additionally, Ames mutagenicity data from FDA/CFSAN was used to create another data set of 1535 chemicals for external validation of the model, yielding 98% coverage, 73% sensitivity, 86% specificity, 81% concordance and 84% negative predictivity. - Highlights: • A new in silico QSAR model to predict Ames mutagenicity is described. • The model is extensively validated with chemicals from the FDA and the public domain. • Validation tests show desirable high sensitivity and high negative predictivity. • The model predicted 14 reportedly difficult to predict drug impurities with accuracy. • The model is suitable to support risk evaluation of potentially mutagenic compounds.« less
Antioxidative and antimutagenic activities of healthy herbal drinks from Chinese medicinal herbs.

PubMed

Chen, Wenlung; Weng, Yih-Ming; Tseng, Chin-Yin

2003-01-01

Twenty-nine Chinese medicinal herbs and three healthy herbal drinks made of those herbs in a food processing pilot plant were tested for their antioxidative, free radical scavenging, mutagenic and antimutagenic activities. Water extracts of herbs (with few exceptions) and herbal drinks showed free radical scavenging activity. All water extracts of herbs and herbal drinks showed no mutagenicity toward Salmonella typhimurium tester strains TA98 and TA100 used in the Ames mutagenic tests. In the antimutagenic tests, the mutagenic activity of 4-nitroquinoline N-oxide (NQNO) toward S. typhimurium TA98 was markedly inhibited by water extracts of herbs and herbal drinks. Based on the results, it is suggested that the herbal drinks manufactured in pilot-plant scale are safe and can be served as health-promoting drinks for the public.
Pointing to potential reference areas to assess soil mutagenicity.

PubMed

Meyer, D D; Da Silva, F M R; Souza, J W M; Pohren, R S; Rocha, J A V; Vargas, V M F

2015-04-01

Several have been performed to evaluate the mutagenicity of soil samples in urban and industrial areas. The use of uncontaminated reference areas has been an obstacle to the study of environmental mutagenesis. The study aimed to indicate a methodology to define reference areas in studies of environmental contamination based on "Ambient Background Concentration" of metallic elements associated with the Salmonella/microsome assay. We looked at three potential reference areas, two of them close by the industrial sources of contamination (São Jerônimo reference, near the coal-fired power plant, and Triunfo reference, near the wood preservative plant), but not directly influenced by them and an area located inside a protected area (Itapuã reference). We also carried out chemical analyses of some metals to plot the metal profile of these potential reference areas and define basal levels of these metals in the soils. After examining the mutagenicity of the inorganic extracts using strains TA98, TA97a, and TA100, in the presence and absence of S9 mix, we indicated the São Jerônimo reference and the Itapuã reference as two sites that could be used in future studies of mutagenicity of soils in southern Brazil. The association between a mutagenicity bioassay and the "Ambient Background Concentration" seems to be a useful method to indicate the reference areas in studies of contamination by environmental mutagens, where these results were corroborated by canonical correspondence analysis.

Computational identification of structural factors affecting the mutagenic potential of aromatic amines: study design and experimental validation.

PubMed

Slavov, Svetoslav H; Stoyanova-Slavova, Iva; Mattes, William; Beger, Richard D; Brüschweiler, Beat J

2018-07-01

A grid-based, alignment-independent 3D-SDAR (three-dimensional spectral data-activity relationship) approach based on simulated 13 C and 15 N NMR chemical shifts augmented with through-space interatomic distances was used to model the mutagenicity of 554 primary and 419 secondary aromatic amines. A robust modeling strategy supported by extensive validation including randomized training/hold-out test set pairs, validation sets, "blind" external test sets as well as experimental validation was applied to avoid over-parameterization and build Organization for Economic Cooperation and Development (OECD 2004) compliant models. Based on an experimental validation set of 23 chemicals tested in a two-strain Salmonella typhimurium Ames assay, 3D-SDAR was able to achieve performance comparable to 5-strain (Ames) predictions by Lhasa Limited's Derek and Sarah Nexus for the same set. Furthermore, mapping of the most frequently occurring bins on the primary and secondary aromatic amine structures allowed the identification of molecular features that were associated either positively or negatively with mutagenicity. Prominent structural features found to enhance the mutagenic potential included: nitrobenzene moieties, conjugated π-systems, nitrothiophene groups, and aromatic hydroxylamine moieties. 3D-SDAR was also able to capture "true" negative contributions that are particularly difficult to detect through alternative methods. These include sulphonamide, acetamide, and other functional groups, which not only lack contributions to the overall mutagenic potential, but are known to actively lower it, if present in the chemical structures of what otherwise would be potential mutagens.
Concomitant Lethal Mutagenesis of Human Immunodeficiency Virus Type 1

PubMed Central

Dapp, Michael J.; Holtz, Colleen M.; Mansky, Louis M.

2012-01-01

RNA virus population dynamics is complex, and sophisticated approaches are needed in many cases for therapeutic intervention. One such approach, termed lethal mutagenesis, is directed at targeting the virus population structure for extinction or error catastrophe. Previous studies have demonstrated the concept of this approach with human immunodeficiency virus type 1 (HIV-1) by use of chemical mutagens (i.e., 5-azacytidine) as well as by host factors with mutagenic properties (i.e., APOBEC3G). In this study, these two unrelated mutagenic agents were used concomitantly to investigate the interplay of these distinct mutagenic mechanisms. Specifically, an HIV-1 was produced from APOBEC3G (A3G)-expressing cells and used to infect permissive target cells treated with 5-azacytidine (5-AZC). Reduced viral infectivity and increased viral mutagenesis was observed with both the viral mutagen (i.e., G-to-C mutations) and the host restriction factor (i.e., G-to-A mutations); however, when combined, had complex interactions. Intriguingly, nucleotide sequence analysis revealed that concomitant HIV-1 exposure to both 5-AZC and A3G resulted in an increase of G-to-A viral mutagenesis at the expense of G-to-C mutagenesis. A3G catalytic activity was required for the diminution in G-to-C mutagenesis. Taken together, our findings provide the first demonstration for potentiation of the mutagenic effect of a cytosine analog by A3G expression, resulting in concomitant HIV-1 lethal mutagenesis. PMID:22426127
The mouse lymphoma thymidine kinase assay for the assessment and comparison of the mutagenic activity of cigarette mainstream smoke particulate phase.

PubMed

Schramke, H; Meisgen, T J; Tewes, F J; Gomm, W; Roemer, E

2006-10-29

The mouse lymphoma thymidine kinase assay (MLA) has been optimized to quantitatively determine the in vitro mutagenicity of cigarette mainstream smoke particulate phase. To test whether the MLA is able to discriminate between different cigarette types, specially constructed cigarettes each containing a single tobacco type - Bright, Burley, or Oriental - were investigated. The mutagenic activity of the Burley cigarette was statistically significantly lower, up to approximately 40%, than that of the Bright and Oriental cigarettes. To determine the impact of two different sets of smoking conditions, American-blend cigarettes were smoked under US Federal Trade Commission/International Organisation for Standardisation conditions and under Massachusetts Department of Public Health (MDPH) conditions. Conventional cigarettes - eight from the US commercial market plus the Reference Cigarettes 1R4F and 2R4F - and an electrically heated cigarette smoking system (EHCSS) prototype were tested. There were no statistically significant differences between the two sets of smoking conditions on a per mg total particulate matter basis, although there was a consistent trend towards slightly lower mutagenic activity under MDPH conditions. The mutagenic activity of the EHCSS prototype was distinctly lower than that of the conventional cigarettes under both sets of smoking conditions. These results show that the MLA can be used to assess and compare the mutagenic activity of cigarette mainstream smoke particulate phase in the comprehensive toxicological assessment of cigarette smoke.
Environmental nitration processes enhance the mutagenic potency of aromatic compounds.

PubMed

Bonnefoy, Aurélie; Chiron, Serge; Botta, Alain

2012-05-01

This work is an attempt to establish if aromatic nitration processes are always associated with an increase of genotoxicity. We determined the mutagenic and genotoxic effects of Benzene (B), Nitrobenzene (NB), Phenol (P), 2-Nitrophenol (2-NP), 2,4-Dinitrophenol (2,4-DNP), Pyrene (Py), 1-Nitropyrene (1-NPy), 1,3-Dinitropyrene (1,3-DNPy), 1,6-Dinitropyrene (1,6-DNPy), and 1,8-Dinitropyrene (1,8-DNPy). The mutagenic activities were evaluated with umuC test in presence and in absence of metabolic activation with S9 mix. Then, we used both cytokinesis-blocked micronucleus (CBMN) assay, in combination with fluorescent in situ hybridization (FISH) of human pan-centromeric DNA probes on human lymphocytes in order to evaluate the genotoxic effects. Analysis of all results shows that nitro polycyclic aromatic hydrocarbons (PAHs) are definitely environmental genotoxic/mutagenic hazards and confirms that environmental aromatic nitration reactions lead to an increase in genotoxicity and mutagenicity properties. Particularly 1-NPy and 1,8-DNPy can be considered as human potential carcinogens. They seem to be significant markers of the genotoxicity, mutagenicity, and potential carcinogenicity of complex PAHs mixtures present in traffic emission and industrial environment. In prevention of environmental carcinogenic risk 1-NPy and 1,8-DNPy must therefore be systematically analyzed in environmental complex mixtures in association with combined umuC test, CBMN assay, and FISH on cultured human lymphocytes. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012. Copyright © 2010 Wiley Periodicals, Inc.
Comparison of Mutagenic Activities of Various Ultra-Fine Particles.

PubMed

Park, Chang Gyun; Cho, Hyun Ki; Shin, Han Jae; Park, Ki Hong; Lim, Heung Bin

2018-04-01

Air pollution is increasing, along with consumption of fossil fuels such as coal and diesel gas. Air pollutants are known to be a major cause of respiratory-related illness and death, however, there are few reports on the genotoxic characterization of diverse air pollutants in Korea. In this study, we investigated the mutagenic activity of various particles such as diesel exhaust particles (DEP), combustion of rice straw (RSC), pine stem (PSC), and coal (CC), tunnel dust (TD), and road side dust (RD). Ultra-fine particles (UFPs) were collected by the glass fiber filter pad. Then, we performed a chemical analysis to see each of the component features of each particulate matter. The mutagenicity of various UFPs was determined by the Ames test with four Salmonella typhimurium strains with or without metabolic activation. The optimal concentrations of UFPs were selected based on result of a concentration decision test. Moreover, in order to compare relative mutagenicity among UFPs, we selected and tested DEP as mutation reference. DEP, RSC, and PSC induced concentration-dependent increases in revertant colony numbers with TA98, TA100, and TA1537 strains in the absence and presence of metabolic activation. DEP showed the highest specific activity among the particulate matters. In this study, we conclude that DEP, RSC, PSC, and TD displayed varying degrees of mutagenicity, and these results suggest that the mutagenicity of these air pollutants is associated with the presence of polycyclic aromatic hydrocarbons (PAHs) in these particulate matters.
Prediction of rodent carcinogenicity bioassays from molecular structure using inductive logic programming

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, R.D.; Srinivasan, A.

1996-10-01

The machine learning program Progol was applied to the problem of forming the structure-activity relationship (SAR) for a set of compounds tested for carcinogenicity in rodent bioassays by the U.S. National Toxicology Program (NTP). Progol is the first inductive logic programming (ILP) algorithm to use a fully relational method for describing chemical structure in SARs, based on using atoms and their bond connectivities. Progol is well suited to forming SARs for carcinogenicity as it is designed to produce easily understandable rules (structural alerts) for sets of noncongeneric compounds. The Progol SAR method was tested by prediction of a set ofmore » compounds that have been widely predicted by other SAR methods (the compounds used in the NTP`s first round of carcinogenesis predictions). For these compounds no method (human or machine) was significantly more accurate than Progol. Progol was the most accurate method that did not use data from biological tests on rodents (however, the difference in accuracy is not significant). The Progol predictions were based solely on chemical structure and the results of tests for Salmonella mutagenicity. Using the full NTP database, the prediction accuracy of Progol was estimated to be 63% ({+-}3%) using 5-fold cross validation. A set of structural alerts for carcinogenesis was automatically generated and the chemical rationale for them investigated-these structural alerts are statistically independent of the Salmonella mutagenicity. Carcinogenicity is predicted for the compounds used in the NTP`s second round of carcinogenesis predictions. The results for prediction of carcinogenesis, taken together with the previous successful applications of predicting mutagenicity in nitroaromatic compounds, and inhibition of angiogenesis by suramin analogues, show that Progol has a role to play in understanding the SARs of cancer-related compounds. 29 refs., 2 figs., 4 tabs.« less
Attesting the efficiency of monitored natural attenuation in the detoxification of sewage sludge by means of genotoxic and mutagenic bioassays.

PubMed

Mazzeo, Dânia Elisa Christofoletti; Fernandes, Thaís Cristina Casimiro; Marin-Morales, Maria Aparecida

2016-11-01

A viable alternative to the use of sewage sludge (SS) would be using it as a reconditioner of agricultural soils, due to its high content of organic matter and nutrients. However, this solution may contaminate the soil, since SS may contain toxic substances. Monitored natural attenuation is a process that can be used in the decontamination of SS before its disposal into the environment. The effectiveness of the natural attenuation of a domestic SS was evaluated over 12 months by assays of Salmonella/microsome and micronucleus (MN) in human hepatoma cells (HepG2). Mutagenic activity was observed for the Salmonella strain TA 100, with S9, for the extracts from periods 0-6 months of natural attenuation. Genotoxic effects were observed in HepG2 cells, for 0 and 2 months, in almost all tested concentrations. Comparing obtained data by MN test to chemical analyses, it is possible to observe a coincidence between the induction of MN and the quantity of the m- and p-cresol, since these compounds were present in the initial SS and after 2 months of natural attenuation, decreasing their concentrations in samples from 6 to 12 months. The positive results obtained with Salmonella/microsome (from 6 months) suggest a combined action of other substances in SS. These results indicated that this SS, in the earlier periods tested, is potentially genotoxic and mutagenic and that its disposal can lead to severe environmental problems. Thus, the use of the studied SS as reconditioner requires pre-processing for over than 6 months of natural attenuation. Copyright © 2016 Elsevier Ltd. All rights reserved.
DNA damage protective effect of honey-sweetened cashew apple nectar in Drosophila melanogaster

PubMed Central

da Silva, Robson Alves; Dihl, Rafael Rodrigues; Dias, Lucas Pinheiro; Costa, Maiane Papke; de Abreu, Bianca Regina Ribas; Cunha, Kênya Silva; Lehmann, Mauricio

2016-01-01

Abstract Fruits and derivatives, such as juices, are complex mixtures of chemicals, some of which may have mutagenic and/or carcinogenic potential, while others may have antimutagenic and/or anticancer activities. The modulating effects of honey-sweetened cashew apple nectar (HSCAN), on somatic mutation and recombination induced by ethyl methanesulfonate (EMS) and mitomycin C (MMC) were evaluated with the wing spot test in Drosophila melanogaster using co- and post-treatment protocols. Additionally, the antimutagenic activity of two HSCAN components, cashew apple pulp and honey, in MMC-induced DNA damage was also investigated. HSCAN reduced the mutagenic activity of both EMS and MMC in the co-treatment protocol, but had a co-mutagenic effect when post-administered. Similar results were also observed with honey on MMC mutagenic activity. Cashew apple pulp was effective in exerting protective or enhancing effects on the MMC mutagenicity, depending on the administration protocol and concentration used. Overall, these results indicate that HSCAN, cashew apple and honey seem capable of modulating not only the events that precede the induced DNA damages, but also the Drosophila DNA repair processes involved in the correction of EMS and MMC-induced damages. PMID:27560988
Identification of polycyclic aromatic hydrocarbons in mutagenic adsorbates to a copper-phthalocyanine derivative recovered from municipal river water.

PubMed

Sayato, Y; Nakamuro, K; Ueno, H; Goto, R

1993-08-01

A study was made to identify polycyclic aromatic hydrocarbons (PAHs) in the mutagenic adsorbate to blue cotton recovered from the water of the Katsura River which is a tributary of the Yodo River, a typical municipal river. As blue cotton bears a covalently bound copper-phthalocyanine derivative which can adsorb PAHs over 3 rings, PAHs in the adsorbate were separated into 4 fractions (I-IV) by Sephadex LH-20 gel chromatography. Fractions III and IV showed high direct and indirect frameshift mutagenicity in strains YG1021 and YG1024, the nitroreductase- and O-acetyltransferase-overproducing derivatives of TA98, especially in YG1024 with S9 mix, whereas these fractions showed less mutagenicity in TA98NR or TA98/1,8-DNP6. These results suggest that mutagenic nitroarenes and aminoarenes are present in both fractions. The retention times of some peaks separated from both fractions using high performance liquid chromatography (HPLC) with a fluorescence detector were identical with those of authentic PAHs. Gas chromatography-mass spectrometry of some HPLC fractions demonstrated that anthraquinone, azulene derivative, quinoline derivative, chrysene and benzo[b]fluoranthene are probably contained in these fractions.
Using Saccharomyces cerevisiae to test the mutagenicity of household compounds: an open ended hypothesis-driven teaching lab.

PubMed

Marshall, Pamela A

2007-01-01

In our Fundamentals of Genetics lab, students perform a wide variety of labs to reinforce and extend the topics covered in lecture. I developed an active-learning lab to augment the lecture topic of mutagenesis. In this lab exercise, students determine if a compound they bring from home is a mutagen. Students are required to read extensive background material, perform research to find a potential mutagen to test, develop a hypothesis, and bring to the lab their own suspected mutagen. This lab uses a specially developed strain of Saccharomyces cerevisiae, D7, to determine if a compound is a mutagen. Mutagenesis of the D7 genome can lead to a scorable alteration in the phenotypes of this strain. Students outline and carry out a protocol for treatment of the yeast tester strain, utilizing the concept of dose/response and positive and negative controls. Students report on their results using a PowerPoint presentation to simulate giving a scientific presentation. The students' self-assessment of their knowledge indicated that, in all cases, the students felt that they knew more about the assay, mutagenesis, and the relationship between genotype and phenotype (P < 0.05) after completing the exercise.
'Petite' mutagenesis and mitotic crossing-over in yeast by DNA-targeted alkylating agents.

PubMed

Ferguson, L R; Turner, P M; Gourdie, T A; Valu, K K; Denny, W A

1989-12-01

Although the biological properties (cytotoxicity, mutagenicity and carcinogenicity) of alkylating agents result from their bonding interactions with DNA, such compounds generally do not show any special binding affinity for DNA. A series of acridine-linked aniline mustards of widely-varying alkylator reactivity have been designed as DNA-directed alkylating agents. We have considered whether such DNA targeting has an effect on mutagenic properties by evaluating this series of drugs in comparison with their untargeted counterparts for toxic, recombinogenic and mutagenic properties in Saccharomyces cerevisiae strain D5. The simple untargeted aniline mustards are effective inducers of mitotic crossing-over in this strain, but resemble other reported alkylators in being rather inefficient inducers of the "petite" or mitochondrial mutation in yeast. However, the majority of the DNA-targeted mustards were very efficient petite mutagens, while showing little evidence of mitotic crossing-over or other nuclear events. The 100% conversion of cells into petites and the lack of a differential between growing and non-growing cells are similar to the effects of the well characterised mitochondrial mutagen ethidium bromide. These data suggest very different modes of action between the DNA-targeted alkylators and their non-targeted counterparts.
A Literature Review-Problem Definition Studies on Selected Toxic Chemicals. Volume 1. Occupational Health and Safety Aspects of Diesel Fuel and White Smoke Generated from It

DTIC Science & Technology

1978-04-01

properties heating oil :mammalian toxicity sampling ABSTRACT (Cotthum an to~" aid* if neoe...m mE ide .Ids bp block ,ninborj Literature is reviewed (75...mutations. Diesel fuel may be excreted from the body in the urine , or exhaled from the lungs. Persons who may be exposed to diesel fuel white smoke should be...37 VIII. Carcinogenicity, Mutagenicity, Teratogenicity 42 IX. Industrial Hygiene Practices and Standards 43 X. Sampling and Analytic Techniques 45
Inhibition of Fried Meat-Induced Colorectal DNA Damage and Altered Systemic Genotoxicity in Humans by Crucifera, Chlorophyllin, and Yogurt

PubMed Central

Shaughnessy, Daniel T.; Gangarosa, Lisa M.; Schliebe, Barbara; Umbach, David M.; Xu, Zongli; MacIntosh, Beth; Knize, Mark G.; Matthews, Peggy P.; Swank, Adam E.; Sandler, Robert S.; DeMarini, David M.; Taylor, Jack A.

2011-01-01

Dietary exposures implicated as reducing or causing risk for colorectal cancer may reduce or cause DNA damage in colon tissue; however, no one has assessed this hypothesis directly in humans. Thus, we enrolled 16 healthy volunteers in a 4-week controlled feeding study where 8 subjects were randomly assigned to dietary regimens containing meat cooked at either low (100°C) or high temperature (250°C), each for 2 weeks in a crossover design. The other 8 subjects were randomly assigned to dietary regimens containing the high-temperature meat diet alone or in combination with 3 putative mutagen inhibitors: cruciferous vegetables, yogurt, and chlorophyllin tablets, also in a crossover design. Subjects were nonsmokers, at least 18 years old, and not currently taking prescription drugs or antibiotics. We used the Salmonella assay to analyze the meat, urine, and feces for mutagenicity, and the comet assay to analyze rectal biopsies and peripheral blood lymphocytes for DNA damage. Low-temperature meat had undetectable levels of heterocyclic amines (HCAs) and was not mutagenic, whereas high-temperature meat had high HCA levels and was highly mutagenic. The high-temperature meat diet increased the mutagenicity of hydrolyzed urine and feces compared to the low-temperature meat diet. The mutagenicity of hydrolyzed urine was increased nearly twofold by the inhibitor diet, indicating that the inhibitors enhanced conjugation. Inhibitors decreased significantly the mutagenicity of un-hydrolyzed and hydrolyzed feces. The diets did not alter the levels of DNA damage in non-target white blood cells, but the inhibitor diet decreased nearly twofold the DNA damage in target colorectal cells. To our knowledge, this is the first demonstration that dietary factors can reduce DNA damage in the target tissue of fried-meat associated carcinogenesis. Trial Registration ClinicalTrials.gov NCT00340743. PMID:21541030
Evaluation of the mutagenicity and carcinogenicity of motor vehicle emissions in short-term bioassays.

PubMed Central

Lewtas, J

1983-01-01

Incomplete combustion of fuel in motor vehicles results in the emission of submicron carbonaceous particles which, after cooling and dilution, contain varying quantities of extractable organic constituents. These organics are mutagenic in bacteria. Confirmatory bioassays in mammalian cells provide the capability of detecting chromosomal and DNA damage in addition to gene mutations. In order to evaluate the mutagenicity of these organics in mammalian cells, extractable organics from particle emissions from several diesel and gasoline vehicles were compared in a battery of microbial, mammalian cell and in vivo bioassays. The mammalian cell mutagenicity bioassays were selected to detect gene mutations, DNA damage, and chromosomal effects. Carcinogenesis bioassays conducted included short-term assays for oncogenic transformation and skin tumorigenesis. The results in different assay systems are compared both qualitatively and quantitatively. Good quantitative correlations were observed between several mutagenesis and carcinogenesis bioassays for this series of diesel and gasoline emissions. PMID:6186475
Mutagenic and antimutagenic effects of aqueous extract of rosemary (Rosmarinus officinalis L.) on meristematic cells of Allium cepa.

PubMed

Felicidade, I; Lima, J D; Pesarini, J R; Monreal, A C D; Mantovani, M S; Ribeiro, L R; Oliveira, R J

2014-11-28

Polyphenolic compounds present in rosemary were found to have antioxidant properties, anticarcinogenic activity, and to increase the detoxification of pro-carcinogens. The aim of the study was to determine the effect the aqueous extract of rosemary (AER) on mutagenicity induced by methylmethane sulfonate in meristematic cells of Allium cepa, as well as to describe its mode of action. Anti-mutagenicity experiments were carried out with 3 different concentrations of AER, which alone showed no mutagenic effects. In antimutagenicity experiments, AER showed chemopreventive activity in cultured meristematic cells of A. cepa against exposure to methylmethane sulfonate. Additionally, post-treatment and simultaneous treatment using pre-incubation protocols were the most effective. Evaluation of different protocols and the percent reduction in DNA indicated bioantimutagenic as well desmutagenic modes of action for AER. AER may be chemopreventive and antimutagenic.
Urine mutagenicity and biochemical effects of the drinking water mutagen, 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone (MX), following repeated oral administration to mice and rats.

PubMed

Meier, J R; Monarca, S; Patterson, K S; Villarini, M; Daniel, F B; Moretti, M; Pasquini, R

1996-06-17

Mutagenicity analysis of urine from rats treated by oral gavage with MX at a dose of 64 mg/kg for 14 days revealed that only 0.3% of the administered compound was excreted in a genotoxically active form. At lower doses, mutagenicity was not detectable. No evidence of micronucleus induction in peripheral blood erythrocytes was observed in mice treated similarly. These findings indicate that MX is extensively detoxified in vivo and is unlikely to cause genetic damage in systemic tissues except at relatively high doses where detoxification pathways become saturated. In a separate experiment, significant depressions were observed in D-glucaric acid and thioether excretion and in levels of several liver enzymes involved in xenobiotic metabolism. The mechanism for these metabolic alterations and their relevance to the in vivo metabolism of the compound require further investigation.
Peptide bond-forming reagents HOAt and HATU are not mutagenic in the bacterial reverse mutation test.

PubMed

Nicolette, John; Neft, Robin E; Vanosdol, Jessica; Murray, Joel

2016-04-01

The peptide bond-forming reagents 1-hydroxy-7-azabenzotriazole (HOAt, CAS 39968-33-7) and O-(7-Azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU, CAS 148893-10-1) either have structural alerts, unclassified features or are considered out of domain when evaluated for potential mutagenicity with in silico programs DEREK and CaseUltra. Since they are commonly used reagents in pharmaceutical drug syntheses, they may become drug substance or drug product impurities and would need to be either controlled to appropriately safe levels or tested for mutagenicity. Both reagents were tested in the bacterial reverse mutation (Ames) test at Covance, under GLP conditions, following the OECD test guideline and ICH S2(R1) recommendations and found to be negative. Our data show that HOAt and HATU-common pharmaceutical synthesis reagents-are not mutagenic, and can be treated as ordinary drug impurities. © 2016 Wiley Periodicals, Inc.
Mutagenicity of chromium picolinate and its components in Salmonella typhimurium and L5178Y mouse lymphoma cells.

PubMed

Whittaker, Paul; San, Richard H C; Clarke, Jane J; Seifried, Harold E; Dunkel, Virginia C

2005-11-01

Chromium picolinate is one of the most commonly used chromium dietary supplements available in the United States, and it has been marketed to consumers for use in weight loss, increasing muscle mass, and lowering serum cholesterol. Chromium picolinate is a synthetic compound that provides a bioavailable form of Cr(III) that is absorbed better than dietary chromium. However, there are several reports that it can have adverse effects. In order to study the mechanism of observed cellular toxicity and mutagenicity, chromium picolinate and its component compounds, chromium (III) chloride and picolinic acid, were evaluated in Salmonella typhimurium and L5178Y mouse lymphoma cells. Neither chromium picolinate nor chromium chloride induced a mutagenic response in S. typhimurium. However, in the L5178Y mouse lymphoma mutation assay, chromium picolinate induced mutagenic responses without and with the addition of S9.
Experimental research on the in vitro antitumor effects of Crataegus sanguinea.

PubMed

Sun, Jianling; Gao, Guolan; Gao, YuLian; Xiong, LiJuan; Li, Xiaoying; Guo, Jihong; Zhang, Yueming

2013-09-01

Crataegus sanguinea is a wild plant, which has been widely grown in the north and south of the Tianshan mountains in Xinjiang. In order to explore their anti-cancer properties, edible wild plants from Xinjiang have been tested for their antitumor properties. We used Ames tests, mouse bone marrow polychromatic erythrocytes micronucleus tests, and tumor cells cultured in vitro to study the anti-mutagenic and anti-tumor effects of C. sanguinea extract. We have shown that C. sanguinea has anti-mutagenic effect, but no mutagenicity. Cell culture in vitro experiments show that there is no inhibition of growth or increase in cell death on normal mouse fibroblasts, but a stronger inhibition of cell growth and an increase in cell death of Hep-2 and MGC-803 tumor cells. The results of this study illustrate that C. sanguinea extract has both anti-mutagenic and anti-tumor effects.
Interactive lethal and mutagenic effects of ultraviolet light and bleomycin in yeast: synergism or antagonism?

PubMed

Lillo, O L; Severgnini, A A; Nunes, E M

1997-11-01

The mutagenic interactions of ultraviolet light and bleomycin in haploid populations of Saccharomyces cerevisiae were analyzed. Survival and mutation frequency as a function of different bleomycin concentrations after one conditioning dose of UV radiation were determined. Furthermore, corresponding interaction functions and sensitization factors were calculated. A synergistic interaction between UV light and bleomycin was shown for both lethal and mutagenic events when the cells were in nutrient broth during the treatments. Conversely, the interaction between UV light and bleomycin was antagonistic when the cells were in deionized water during the treatment. The magnitude of lethal and mutagenic interactions depends on dose, and thus presumably on the number of lesions. The observed interactions between UV light and bleomycin suggest that the mechanism that is most likely involved is the induction of repair systems with different error probabilities during the delay of cell division.

Problem-Solving Support for English Language Learners

ERIC Educational Resources Information Center

Wiest, Lynda R.

2008-01-01

Although word problems pose greater language demands, they also encourage more meaningful problem solving and mathematics understanding. With proper instructional support, a student-centered, investigative approach to contextualized problem solving benefits all students. This article presents a lesson built on an author-adapted version of the…
Detection of 1-nitropyrene in yakitori (grilled chicken).

PubMed

Kinouchi, T; Tsutsui, H; Ohnishi, Y

1986-01-01

Pieces of raw chicken with or without a marinating sauce were grilled over a city gas flame, extracted with benzene-ethanol (4:1) by ultrasonication and fractionated into diethyl ether-soluble neutral, acidic and basic fractions. The mutagenicity of these fractions was measured with Salmonella typhimurium strains TA100, TA98, TA98NR and TA98/1,8-DNP6 in the presence and absence of a 9000 X g post-mitochondrial supernatant from Aroclor 1254-treated Sprague-Dawley rat liver (S9 mix). The basic fraction of yakitori without the sauce was more mutagenic than the other fractions for S. typhimurium strain TA98 in the presence of S9 mix. This is probably due to the presence of amino acid or protein pyrolysates. However, when the chicken was grilled with the sauce, the basic fraction showed lower mutagenicity for strain TA98 in the presence of S9 mix than did the same fraction without the sauce. The neutral fraction of yakitori with sauce showed high mutagenicity for strain TA98 in the absence of S9 mix, but low mutagenicity for strains TA98NR and TA98/1,8-DNP6, suggesting that this fraction might contain nitropyrenes (NPs). The neutral fraction of yakitori was analyzed by high-performance liquid chromatography (HPLC). The neutral fraction of the chicken grilled with the sauce for 3, 5 and 7 min contained 3.8, 19 and 43 ng, respectively, of 1-NP per gram of yakitori accounting for 3.0, 2.7 and 1.3%, respectively, of the total mutagenicity.(ABSTRACT TRUNCATED AT 250 WORDS)
Prediction of genotoxic potential of cosmetic ingredients by an in silico battery system consisting of a combination of an expert rule-based system and a statistics-based system.

PubMed

Aiba née Kaneko, Maki; Hirota, Morihiko; Kouzuki, Hirokazu; Mori, Masaaki

2015-02-01

Genotoxicity is the most commonly used endpoint to predict the carcinogenicity of chemicals. The International Conference on Harmonization (ICH) M7 Guideline on Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals to Limit Potential Carcinogenic Risk offers guidance on (quantitative) structure-activity relationship ((Q)SAR) methodologies that predict the outcome of bacterial mutagenicity assay for actual and potential impurities. We examined the effectiveness of the (Q)SAR approach with the combination of DEREK NEXUS as an expert rule-based system and ADMEWorks as a statistics-based system for the prediction of not only mutagenic potential in the Ames test, but also genotoxic potential in mutagenicity and clastogenicity tests, using a data set of 342 chemicals extracted from the literature. The prediction of mutagenic potential or genotoxic potential by DEREK NEXUS or ADMEWorks showed high values of sensitivity and concordance, while prediction by the combination of DEREK NEXUS and ADMEWorks (battery system) showed the highest values of sensitivity and concordance among the three methods, but the lowest value of specificity. The number of false negatives was reduced with the battery system. We also separately predicted the mutagenic potential and genotoxic potential of 41 cosmetic ingredients listed in the International Nomenclature of Cosmetic Ingredients (INCI) among the 342 chemicals. Although specificity was low with the battery system, sensitivity and concordance were high. These results suggest that the battery system consisting of DEREK NEXUS and ADMEWorks is useful for prediction of genotoxic potential of chemicals, including cosmetic ingredients.
Potential impurities in drug substances: Compound-specific toxicology limits for 20 synthetic reagents and by-products, and a class-specific toxicology limit for alkyl bromides.

PubMed

Bercu, J P; Galloway, S M; Parris, P; Teasdale, A; Masuda-Herrera, M; Dobo, K; Heard, P; Kenyon, M; Nicolette, J; Vock, E; Ku, W; Harvey, J; White, A; Glowienke, S; Martin, E A; Custer, L; Jolly, R A; Thybaud, V

2018-04-01

This paper provides compound-specific toxicology limits for 20 widely used synthetic reagents and common by-products that are potential impurities in drug substances. In addition, a 15 μg/day class-specific limit was developed for monofunctional alkyl bromides, aligning this with the class-specific limit previously defined for monofunctional alkyl chlorides. Both the compound- and class-specific toxicology limits assume a lifetime chronic exposure for the general population (including sensitive subpopulations) by all routes of exposure for pharmaceuticals. Inhalation-specific toxicology limits were also derived for acrolein, formaldehyde, and methyl bromide because of their localized toxicity via that route. Mode of action was an important consideration for a compound-specific toxicology limit. Acceptable intake (AI) calculations for certain mutagenic carcinogens assumed a linear dose-response for tumor induction, and permissible daily exposure (PDE) determination assumed a non-linear dose-response. Several compounds evaluated have been previously incorrectly assumed to be mutagenic, or to be mutagenic carcinogens, but the evidence reported here for such compounds indicates a lack of mutagenicity, and a non-mutagenic mode of action for tumor induction. For non-mutagens with insufficient data to develop a toxicology limit, the ICH Q3A qualification thresholds are recommended. The compound- and class-specific toxicology limits described here may be adjusted for an individual drug substance based on treatment duration, dosing schedule, severity of the disease and therapeutic indication. Copyright © 2018. Published by Elsevier Inc.
Evaluation of mutagenic and antimutagenic activities of neem (Azadirachta indica) seed oil in the in vitro Ames Salmonella/microsome assay and in vivo mouse bone marrow micronucleus test.

PubMed

Vinod, V; Tiwari, P K; Meshram, G P

2011-04-12

The possible mutagenic and antimutagenic activity of neem oil (NO) and its DMSO extract (NDE) were, examined in the Ames Salmonella/microsome mutagenicity test and the mouse bone marrow micronucleus assay. Eight different strains of Salmonella typhimurium were, used to study the genotoxicity of neem oil both in the presence and absence of Aroclor-1254 induced rat liver homogenate (S9). Two-dose treatment protocol was, employed to study the cytogenetic activity in micronucleus assay. Similarly, the antimutagenic activity of neem oil and NDE was studied against mitomycin (MMC) and 7,12-dimethylbenz[a]anthracene (DMBA) in the above two test systems. Neem oil was non-mutagenic in all the eight tester strains of Salmonella typhimurium both in the presence and absence of S9 mix. In the present study, there was no significant increase in the frequency of micronucleated polychromatic erythrocytes (MNPCEs) in neem oil treated groups over the negative control (DMSO) group of animals, indicating the non-clastogenic activity of neem oil in the micronucleus test. Neem oil showed good antimutagenic activity against DMBA induced mutagenicity compared to its DMSO extract. However, neem oil showed comparatively less antimutagenicity against MMC in the Ames assay. In vivo anticlastogenic assays shows that neem oil exhibited better activity against DMBA induced clastogenicity. These results indicate non-mutagenic activity of neem oil and significant antimutagenic activity of neem oil suggesting its pharmacological importance for the prevention of cancer. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Composition, toxicity, and mutagenicity of particulate and semivolatile emissions from heavy-duty compressed natural gas-powered vehicles.

PubMed

Seagrave, JeanClare; Gigliotti, Andrew; McDonald, Jacob D; Seilkop, Steven K; Whitney, Kevin A; Zielinska, Barbara; Mauderly, Joe L

2005-09-01

Particulate matter (PM) and vapor-phase semivolatile organic compounds (SVOC) were collected from three buses fueled by compressed natural gas. The bus engines included a well-functioning, conventional engine; a "high emitter" engine; and a new technology engine with an oxidation catalyst. Chemical analysis of the emissions showed differences among these samples, with the high emitter sample containing markers of engine oil constituents. PM + SVOC samples were also collected for mutagenicity and toxicity testing. Extraction efficiencies from the collection media were lower than for similarly collected samples from gasoline or diesel vehicles. Responses to the recovered samples were compared on the basis of exhaust volume, to incorporate the emission rates into the potency factors. Mutagenicity was assessed by Salmonella reverse mutation assay. Mutagenicity was greatest for the high emitter sample and lowest for the new technology sample. Metabolic activation reduced mutagenicity in strain TA100, but not TA98. Toxicity, including inflammation, cytotoxicity, and parenchymal changes, was assessed 24 h after intratracheal instillation into rat lungs. Lung responses were generally mild, with little difference between the responses to equivalent volumes of emissions from the normal emitter and the new technology, but greater responses for the high emitter. These emission sample potencies are further compared on the basis of recovered mass with previously reported samples from normal and high-emitter gasoline and diesel vehicles. While mutagenic potencies for the CNG emission samples were similar to the range observed in the gasoline and diesel emission samples, lung toxicity potency factors were generally lower than those for the gasoline and diesel samples.
Urinary mutagenicity and N-acetylation phenotype in textile industry workers exposed to arylamines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinues, B.; Perez, J.; Bernal, M.L.

1992-09-15

Primary aromatic amines have been identified epidemiologically as human carcinogens. It has been suggested that the target organ affected by aromatic amines is dependent on the rate of metabolic activation. Epidemiological studies have shown an association between low acetyl transferase activity and bladder cancer risk. On this basis, our working hypothesis was that the slow acetylators could follow in a higher extent the metabolic pathway independent of N-acetylation, leading to the excretion of conjugates of electrophyles with glucuronic acid. The instability of these glucuronides could be responsible for the association between arylamine-induced bladder cancer and slow acetylator phenotype. A totalmore » of 153 individuals were included in this study: 70 exposed to arylamines (working in textile industry) and 83 nonexposed. The following parameters were determined in urine: mutagenic index in the absence of metabolic activation, S9; mutagenic index in the presence of S9; and the mutagenic index after incubation of the urine with beta-glucuronidase. All individuals were phenotyped according to their capacity of N-acetylation by using isoniazid as drug test. The results show that the mutagenic index after incubation of the urine with beta-glucuronidase is statistically higher in exposed subjects when compared with nonexposed individuals (P less than 0.001), this parameter being statistically higher among exposed subjects who were slow acetylators than among rapid metabolizers, independent of the fact that they were smokers or nonsmokers. There were no significant differences between groups for the mutagenicity in urine not incubated with beta-glucuronidase.« less
Seasonal Fluctuations in Air Pollution in Dazaifu, Japan, and Effect of Long-Range Transport from Mainland East Asia.

PubMed

Coulibaly, Souleymane; Minami, Hiroki; Abe, Maho; Hasei, Tomohiro; Sera, Nobuyuki; Yamamoto, Shigekazu; Funasaka, Kunihiro; Asakawa, Daichi; Watanabe, Masanari; Honda, Naoko; Wakabayashi, Keiji; Watanabe, Tetsushi

2015-01-01

To clarify the seasonal fluctuations in air pollution and the effect of long-range transport, we collected airborne particles (n=118) at Dazaifu in Fukuoka, Japan, from June 2012 to May 2013 and measured Pb and SO4(2-), which are indicators of the long-range transport of anthropogenic air pollutants, as well as their mutagenicity, and other factors. The levels of airborne particles, Pb, and SO4(2-) were very high on March 4, 8, 9, and 19, and May 13, 21, and 22, 2013. The backward trajectories indicated that air masses had arrived from the Gobi Desert and northern China on those days. The mutagenicity of airborne particles was examined using the Ames test on Salmonella typhimurium YG1024. Highly mutagenic airborne particles were mostly collected in winter, and most of them showed high activity both with and without S9 mix. High levels of polycyclic aromatic hydrocarbons (PAHs) were found in many samples that showed high mutagenicity. For the samples collected on January 30, February 21, and March 4, the levels of Pb, SO4(2-), PAHs, and mutagenicity were high, and the backward trajectories indicated that air masses present on those days had passed through northern or central China. The Japan Meteorological Agency registered Asian dust events at Fukuoka on March 8, 9, and 19, 2013. The results of the present study suggest that high levels of anthropogenic air pollutants were transported with Asian dust. Similarly, long-range transport of air pollutants including mutagens occurred on days when Asian dust events were not registered.
Genotoxicity assessment of magnetic iron oxide nanoparticles with different particle sizes and surface coatings

NASA Astrophysics Data System (ADS)

Liu, Yanping; Xia, Qiyue; Liu, Ying; Zhang, Shuyang; Cheng, Feng; Zhong, Zhihui; Wang, Li; Li, Hongxia; Xiao, Kai

2014-10-01

Magnetic iron oxide nanoparticles (IONPs) have been widely used for various biomedical applications such as magnetic resonance imaging and drug delivery. However, their potential toxic effects, including genotoxicity, need to be thoroughly understood. In the present study, the genotoxicity of IONPs with different particle sizes (10, 30 nm) and surface coatings (PEG, PEI) were assessed using three standard genotoxicity assays, the Salmonella typhimurium reverse mutation assay (Ames test), the in vitro mammalian chromosome aberration test, and the in vivo micronucleus assay. In the Ames test, SMG-10 (PEG coating, 10 nm) showed a positive mutagenic response in all the five test bacterial strains with and without metabolic activation, whereas SEI-10 (PEI coating, 10 nm) showed no mutagenesis in all tester strains regardless of metabolic activation. SMG-30 (PEG coating, 30 nm) was not mutagenic in the absence of metabolic activation, and became mutagenic in the presence of metabolic activation. In the chromosomal aberration test, no increase in the incidence of chromosomal aberrations was observed for all three IONPs. In the in vivo micronucleus test, there was no evidence of increased micronuclei frequencies for all three IONPs, indicating that they were not clastogenic in vivo. Taken together, our results demonstrated that IONPs with PEG coating exhibited mutagenic activity without chromosomal and clastogenic abnormalities, and smaller IONPs (SMG-10) had stronger mutagenic potential than larger ones (SMG-30); whereas, IONPs with SEI coating (SEI-10) were not genotoxic in all three standard genotoxicity assays. This suggests that the mutagenicity of IONPs depends on their particle size and surface coating.
Genotoxicity testing: progress and prospects for the next decade.

PubMed

Turkez, Hasan; Arslan, Mehmet E; Ozdemir, Ozlem

2017-10-01

Genotoxicity and mutagenicity analyses have a significant role in the identification of hazard effects of therapeutic drugs, cosmetics, agrochemicals, industrial compounds, food additives, natural toxins and nanomaterials for regulatory purposes. To evaluate mutagenicity or genotoxicity, different in vitro and in vivo methodologies exert various genotoxicological endpoints such as point mutations, changes in number and structure of chromosomes. Areas covered: This review covered the basics of genotoxicity and in vitro/in vivo methods for determining of genetic damages. The limitations that have arisen as a result of the common use of these methods were also discussed. Finally, the perspectives of further prospects on the use of genotoxicity testing and genotoxic mode of action were emphasized. Expert opinion: The solution of actual and practical problems of genetic toxicology is inarguably based on the understanding of DNA damage mechanisms at molecular, subcellular, cellular, organ, system and organism levels. Current strategies to investigate human health risks should be modified to increase their performance for more reliable results and also new techniques such as toxicogenomics, epigenomics and single cell approaches must be integrated into genetic safety evolutions. The explored new biomarkers by the omic techniques will provide forceful genotoxicity assessment to reduce the cancer risk.
GERM-LINE SPECIFIC FACTORS IN CHEMICAL MUTAGENESIS

EPA Science Inventory

Chemical mutagenesis test results ave not revealed evidence of germ-line specific mutagens. owever, conventional assays have indicated that there are male-female differences in mutagenic response, as well as quantitative/qualitative differences in induced mutations which depend u...
Mutagenicity of food-derived carcinogens and the effect of antioxidant vitamins.

PubMed

Montgomery, Beverly A; Murphy, Jessica; Chen, James J; Desai, Varsha G; McGarrity, Lynda; Morris, Suzanne M; Casciano, Daniel A; Aidoo, Anane

2002-01-01

The food-derived heterocyclic amines (HCAs) 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) are mutagenic in the Ames test and produce tumors in laboratory animals, including monkeys. These HCAs have also been shown to induce gene mutations in vivo. To assess the antimutagenic effects of dietary antioxidant vitamins, beta-carotene, ascorbic acid (vitamin C), and alpha-tocopherol (vitamin E), on food-borne mutagenes/carcinogens, we evaluated the mutagenic activity of the compounds alone or combined with antioxidant vitamins. We utilized the rat lymphocyte mutation assay at the hypoxanthine guanine phosphoribosyl transferase (Hprt) locus. Female Fischer 344 rats treated with different doses (0, 2.5, 5.0, 25.0, and 50.0 mg/kg) of the carcinogens were sacrificed 5 wk after mutagen treatment. Although IQ and MeIQ slightly increased mutation frequency (MF) at some doses, a significant (P < 0.0009) increase in MF was found in animals exposed to MeIQx at 25 mg/kg. PhIP was the most mutagenic of the HCAs, with increases (P < 0.0001) in MF detected at all dose levels compared with controls. Because PhIP was the most mutagenic, it was selected for studies using the dietary antioxidant vitamins. Addition of antioxidant vitamins, singly or in a mixture, caused a significant (P < 0.0001) decrease in PhIP-induced Hprt MF. Vitamin E was the most effective at decreasing Hprt MF. In addition, we determined whether carcinogen metabolism would be affected by ingestion of vitamins. The activities of endogenous detoxification enzymes, glutathione S-transferase and glutathione peroxidase (GPx), were thus examined. Intake of beta-carotene and vitamin C without the carcinogen resulted in an increase (P < 0.05) in GPx activity. Also a modest increase in GPx activity was seen in animals that received the antioxidant mixture alone. Although the mechanisms of action of the antioxidants remain to be determined, the results indicate that dietary-derived HCA treatment induced MF in rat lymphocytes and suggest that antioxidants in food or taken as supplements could, in part, counteract such mutagenic activities.
History of the science of mutagenesis from a personal perspective.

PubMed

Malling, Heinrich V

2004-01-01

A career in the study of mutagenesis spanning 50 years is a gift few scientists have been bestowed. My tenure in the field started in 1953, the year the structure of DNA became known (Watson and Crick [1953]: Nature 171:737). Before that time, it was suspected that DNA was the genetic material based on the research of Oswald T. Avery (Avery et al. [1944]: J Exp Med 79:137), but many scientists still believed that proteins or polysaccharides could be the genetic material. The present article describes a lifetime of personal experience in the field of chemical mutagenesis. The methods used to treat viruses with chemical mutagens were well developed in the 1950s. Here I review the early use of nitrous acid and hydroxylamine as mutagens in eukaryotes, the development of methods for the metabolic activation of mutagens by microsomal preparations, and the selection of a mutant tester set for the qualitative characterization of the mutagenic activity of chemicals. These studies provided critical background information that was used by Bruce Ames in the development of his Salmonella/microsome assay, widely known as the Ames test (Ames et al. [1973]: Proc Nat Acad Sci USA 70:2281-2285). This article also describes how a set of diagnostic chemical mutagens was selected and used to identify the molecular nature of gene mutations. Today, DNA sequencing has replaced the use of diagnostic mutagens, but studies of this kind formed the foundation of modern mutation research. They also helped set the stage for the organization of the Environmental Mutagen Society and the Environmental Mutagen Information Center, which are described. The article ends with the development of mammalian single-cell mutation assays, the first system for studying in vivo mutagenesis using recoverable vectors in transgenic animals, other mutation assays in intact mammals, and my thoughts on the critically important area of germ cell mutagenesis. This narrative is not a complete autobiographical account, in that I have selected only those experiences that I feel are important for the history of the field and the edification of today's students. I hope I have shown that science not only is a valuable pursuit but can also be fun, stimulating, and satisfying. A good sense of humor and the knowledge that many discoveries come by serendipity are essential.
Quelques problemes poses a la grammaire casuelle (Some Problems Regarding Case Grammar)

ERIC Educational Resources Information Center

Fillmore, Charles J.

1975-01-01

Discusses problems related to case grammar theory, including: the organizations of a case grammar; determination of semantic roles; definition and hierarchy of cases; cause-effect relations; and formalization and notation. (Text is in French.) (AM)
True Experimental Design.

ERIC Educational Resources Information Center

Huck, Schuyler W.

1991-01-01

This poem, with stanzas in limerick form, refers humorously to the many threats to validity posed by problems in research design, including problems of sample selection, data collection, and data analysis. (SLD)
Research Mathematicians' Practices in Selecting Mathematical Problems

ERIC Educational Resources Information Center

Misfeldt, Morten; Johansen, Mikkel Willum

2015-01-01

Developing abilities to create, inquire into, qualify, and choose among mathematical problems is an important educational goal. In this paper, we elucidate how mathematicians work with mathematical problems in order to understand this mathematical process. More specifically, we investigate how mathematicians select and pose problems and discuss to…
Characterising the Cognitive Processes in Mathematical Investigation

ERIC Educational Resources Information Center

Yeo, Joseph B. W.; Yeap, Ban Har

2010-01-01

Many educators believe that mathematical investigation involves both problem posing and problem solving, but some teachers have taught their students to investigate during problem solving. The confusion about the relationship between investigation and problem solving may affect how teachers teach their students and how researchers conduct their…
MUTAGENICITY IN SALMONELLA OF SULFUR-CONTAINING POLYCYCLIC AROMATIC HETEROCYCLES AND THEIR DIHYDRODIOL DERIVATIVES

EPA Science Inventory

Polycyclic aromatic sulfur heterocycles (PASH) are common constituents of cigarette smoke, fossil fuel-derived materials, and their combustion byproducts. Many PASH are known mutagens and carcinogens. However, unlike their nonsulfur-containing counterparts, relatively little is k...
The mutagenicity of cassava (Manihot esculenta Crantz) preparations.

PubMed

De Meester, C; Rollmann, B; Mupenda, K; Mary, Y

1990-01-01

Different cassava products were found to contain mutagenic activities in the Ames test. This paper describes how the flavonol quercetin is released during the cooking of fresh cassava leaves, following a process very similar to culinary habits. The hydrolysis of the glucoside(s) and the release of free quercetin has been followed by the monitoring of mutagenic activities with a simultaneous isolation and purification by thin-layer chromatography. The fluorodensitometric method applied revealed that fresh leaves contained about 1300 mg quercetin per kg wet weight, of which 800 mg were released during a normal cooking process.
Mutagenic, cytotoxic, and teratogenic effects of 2-acetylaminofluorene and reactive metabolites in vitro.

PubMed

Faustman-Watts, E M; Yang, H Y; Namkung, M J; Greenaway, J C; Fantel, A G; Juchau, M R

1984-01-01

The embryotoxic, mutagenic, and cytotoxic properties of 2-acetylaminofluorene (AAF) and two of its reactive metabolites, N-acetoxy-2-acetylaminofluorene (AAAF) and 2-nitrosofluorene (NF) were assessed in vitro. A combined embryo culture/biotransformation system was used to determine the ability of these compounds to produce embryonic malformations, growth retardation, and/or embryolethality. Salmonella typhimurium auxotrophs (his-) were utilized to measure the mutagenic and cytotoxic potentials of these compounds. The parent compound, AAF, did not produce embryonic malformations or mutagenicity in the absence of an added cytochrome P-450-dependent monooxygenase system. Both metabolites produced each of the measured toxic effects without supplementation of a bioactivation system. However, the three chemicals each elicited a different spectrum of malformations. Bioactivated AAF produced neural tube abnormalities, whereas embryos treated with AAAF primarily exhibited prosencephalic malformations, and NF produced abnormalities of axial rotation or flexure. NF was approximately ten times more potent than AAAF as a direct-acting mutagen but only slightly more active in producing embryonic malformations in vitro. The results indicated that differential effects on the various measured parameters could be produced by these chemicals. The results indicated further that neither NF nor AAAF appeared to be individually responsible for the neural tube abnormalities generated by biotransformed AAF.

Improved method for mutagenicity testing of gaseous compounds by using a gas sampling bag.

PubMed

Araki, A; Noguchi, T; Kato, F; Matsushima, T

1994-05-01

A simple and safety gas exposure method was developed using a gas sampling bag as an exposure vessel and a preparation vessel of diluted gas. The gas exposure conditions such as amount of S9 in the plate, volume of gas for the plate, amount of top agar, exposure period and exposure temperature were examined by mutagenicity testing of 1,3-butadiene using the gas sampling bag. Mutagenicity tests of 14 compounds and 1,3-butadiene on S. typhimurium TA98, TA100, TA1535 and TA1537, and E. coli WP2 uvrA were also examined by the developed gas exposure method. 1,3-Butadiene, propyne (methyl acetylene), monochlorodifluoromethane, ethylchloride, diborane and silane were mutagenic. 1-Butene, 2-butene, 2-methylpropene, methyl vinyl ether, trichlorofluoromethane, dichlorodifluoromethane, 1,2-dichloro-1,1,2,2-tetrafluoroethane, 1,1-difluoroethane and phosphine were not mutagenic on S. typhimurium TA98, TA100, TA1535 and TA1537, and E. coli WP2 uvrA with or without metabolic activation. These results were compatible with a previous report, and this developed method has the advantage that it can be tested easily and safely for combustible and self-combustible substances such as 1,3-butadiene and silane.
Influence of particulate trap oxidizers on emission of mutagenic compounds by diesel automobiles.

PubMed

Rasmussen, R E; Devillez, G; Smith, L R

1989-06-01

Diesel exhaust particles are known to contain mutagenic and carcinogenic chemicals. The aim of this study was to determine whether, and to what extent, catalytic particulate trap oxidizers on light-duty diesel engines may reduce the emission of particle-associated mutagenic chemicals into the environment. Exhaust particles were collected from Mercedes Benz and Volkswagen diesel automobiles, equipped with or without the manufacturer's exhaust traps, while running on a chassis dynamometer under specified load conditions. Exhaust particles were collected from a dilution tunnel onto 20" X 20" Teflon-coated fiberglass filters. Mutagenesis tests of dichloromethane (DCM) extracts of the particles were conducted using the Ames Salmonella bacterial test system. The mutation rate was calculated in terms of histidine revertants per mile of travel during a set of standard test cycles. With both vehicles the traps produced an 87-92% reduction in the total amount of particulate material collected by the filters. There was no significant change in the specific mutagenic activity (revertants per microgram of DCM particle extract) with or without the traps. These studies support the notion that installation of exhaust traps which reduce particulate emission on diesel-powered vehicles will also reduce the emission of particle-associated mutagenic and carcinogenic materials into the environment.
Mutagenic activities of heterocyclic amines in Chinese hamster lung cells in culture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Terada, M.; Nagao, M.; Nakayasu, M.

1986-01-01

A mutation assay system with Chinese hamster lung cells (CHL) using diphtheria toxin resistance as a selective marker has been established. The mutagenic activities of heterocyclic amines, originally isolated from pyrolyzates of amino acids and proteins, broiled fish and fried beef were assayed in cultured CHL cells in the absence and presence of a metabolic activation system, with diphtheria toxin resistance as a marker. All the heterocyclic amines tested except 3-amino-1,4-dimethyl-5H-pyrido (4,3-b)indole (Trp-P-1) required the presence of a metabolic activation system for mutagenicity on CHL cells. 3-Amino-1-methyl-5H-pyrido(4,3-b)indole (Trp-P-2) was the most mutagenic among the heterocyclic amines tested. Other compounds weremore » also mutagenic in the following order of decreasing potency: Trp-P-1, 2-amino-3,4-dimethylimidazo(4,5-f)quinoline (MeIQ), 2-amino-3-methylimidazo(4,5-f)quinoline (IQ), 2-amino-9H-pyrido(2,3-b)indole (A..cap alpha..C), 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline (MeIQx), 2-amino-6-methyldipyrido(1,2-a:3',2'-d)imidazole (Glu-P-1) and 2-aminodipyrido(1,2--a:3',2'-d)imidazole (Glu-P-2).« less
Mutagenicity and antimutagenicity of Baccharis dracunculifolia extract in chromosomal aberration assays in Chinese hamster ovary cells.

PubMed

Munari, Carla Carolina; Resende, Flávia Aparecida; Alves, Jacqueline Morais; de Sousa, João Paulo; Bastos, Jairo Kenupp; Tavares, Denise Crispim

2008-09-01

Baccharis dracunculifolia De Candole (Asteraceae), a native plant from the Brazilian "cerrado", is widely used in folk medicine as an anti-inflammatory agent and for the treatment of gastrointestinal diseases. B. dracunculifolia has been described as the most important plant source of propolis in southeastern Brazil, which is called green propolis due to its color. The aim of the present study was to evaluate the mutagenic and antimutagenic effects of the ethyl acetate extract of B. dracunculifolia leaves (Bd-EAE) on Chinese hamster ovary cells. On one hand, the results showed a significant increase in the frequencies of chromosome aberrations at the highest Bd-EAE concentration tested (100 microg/mL). On the other hand, the lowest Bd-EAE concentration tested (12.5 micro/mL) significantly reduced the chromosome damage induced by the chemotherapeutic agent doxorubicin. The present results indicate that Bd-EAE has the characteristics of a so-called Janus compound, that is, Bd-EAE is mutagenic at higher concentrations, whereas it displays a chemopreventive effect on doxorubicin-induced mutagenicity at lower concentrations. The constituents of B. dracunculifolia responsible for its mutagenic and antimutagenic effects are probably flavonoids and phenylpropanoids, since these compounds can act either as pro-oxidants or as free radical scavengers depending on their concentration.
Predictive Models for Carcinogenicity and Mutagenicity ...

EPA Pesticide Factsheets

Mutagenicity and carcinogenicity are endpoints of major environmental and regulatory concern. These endpoints are also important targets for development of alternative methods for screening and prediction due to the large number of chemicals of potential concern and the tremendous cost (in time, money, animals) of rodent carcinogenicity bioassays. Both mutagenicity and carcinogenicity involve complex, cellular processes that are only partially understood. Advances in technologies and generation of new data will permit a much deeper understanding. In silico methods for predicting mutagenicity and rodent carcinogenicity based on chemical structural features, along with current mutagenicity and carcinogenicity data sets, have performed well for local prediction (i.e., within specific chemical classes), but are less successful for global prediction (i.e., for a broad range of chemicals). The predictivity of in silico methods can be improved by improving the quality of the data base and endpoints used for modelling. In particular, in vitro assays for clastogenicity need to be improved to reduce false positives (relative to rodent carcinogenicity) and to detect compounds that do not interact directly with DNA or have epigenetic activities. New assays emerging to complement or replace some of the standard assays include VitotoxTM, GreenScreenGC, and RadarScreen. The needs of industry and regulators to assess thousands of compounds necessitate the development of high-t
Radiation and chemical mutagen induced somaclonal variations through in vitro organogenesis of cotton (Gossypium hirsutum L.).

PubMed

Muthusamy, Annamalai; Jayabalan, Narayanasamy

2014-12-01

The purpose of the investigation was to induce somaclonal variations by gamma rays (GR), ethylmethane sulphonate (EMS) and sodium azide (SA) during in vitro organogenesis of cotton. The shoot tip explants were irradiated with 5-50 Gray (Gy) GR (Cobalt 60), 0.5-5.0 mM EMS and SA separately, and inoculated on Murashige and Skoog (MS) medium fortified with plant growth regulator (PGR) for organogenesis. The plantlets with well-developed root systems were acclimatized and transferred into the experimental field to screen the somaclonal variations during growth and development. The number of somaclonal variations was observed in growth of irradiated/treated shoot tips, multiplication, plantlet regeneration and growth in vitro and ex vitro. The lower doses/concentrations of mutagenic treatments showed significant enhancement in selected agronomical characters and they showed decreased trends with increasing doses/concentrations of mutagenic agents. The results of the present study revealed the influence of lower doses/concentrations of mutagenic treatments on in vitro and ex vitro growth of cotton plantlets and their significant improvement in agronomical characters which needs further imperative stability analysis. The present observations showed the platform to use lower doses/concentrations of mutagenic agents to induce variability for enhanced agronomical characters, resistant and tolerant cotton varieties.
Dietary Exposure of Nigerians to Mutagens and Estrogen-Like Chemicals

PubMed Central

Omoruyi, Iyekhoetin Matthew; Ahamioje, Derek; Pohjanvirta, Raimo

2014-01-01

Food and drinking water are poorly delineated sources of human exposure to chemical food mutagens and endocrine-disrupting chemicals. In this study, we investigated the presence of mutagens and chemicals exhibiting estrogenic activity in the daily diet of Nigerians, using in vitro assays. Commercially processed foods or snacks and various brands of pure water sachets were extracted by solid-phase extraction and liquid-liquid extraction, respectively. Mutagenicity was determined by the conventional Ames test and two complementary assays on two strains of Salmonella (TA 100 and TA 98), while the estrogenic activity was assessed by a yeast bioluminescent assay, using two recombinant yeast strains (Saccharomyces cerevisiae BMAEREluc/ERα and S. cerevisiae BMA64/luc). A third of the food varieties investigated (chin-chin, hamburger, suya and bean cake) were mutagenic in all three assays, either in the presence or absence of S9 mix. Of the packed water samples, five out of the sixteen investigated (31%), were found to be estrogenic, with estradiol and bisphenol A equivalents ranging from 0.79 to 44.0 ng/L and 124.2 to 1,000.8 ng/L, respectively. Hence, although the current situation in Nigeria does not appear to be substantially worse than, e.g., in Europe, regular monitoring is warranted in the future. PMID:25153465
Bioassay-directed fractionation of organic compounds associated with airborne particulate matter; An interseasonal study

NASA Astrophysics Data System (ADS)

Greenberg, Arthur; Lwo, Jung-Hen; Antherholt, Thomas B.; Rosen, Robert; Hartman, Thomas; Butler, James; Louis, Judy

Bioassay-directed fractionation based upon a modification of a published technique is applied to the study of three seasonal composites of dichloromethane extracts of inhalable particulate matter collected in Newarks, New Jersey The "profiles" of mass distribution and Salmonella TA98 mutagenic activity vs polarity are similar for the three seasons. Only at the second and especially the third fractionation levels are significant differents seen with a slight shift toward more polar compounds during summer. In all three seasons, polar neutral compounds make the greatest contribution toward mutagenic activity. Hydroxynitropolyciclic aromatic hydrocarbons are difficult to analyse by GC/MS) (El and negative chemical ionization), but HPLC/UV appears to be useful. A number of techniques are emplited in the analysis of specific compounds and classes of compounds. Subsequent acetone extraction of filters yields highly polar mutagens where the acidic fractions account for most of the mutagenic activity. These compounds show significantly enhanced mutagenic activity with TA100 relative to TA98 suggesting the presence of highly polar, acidic substances that are strong alkylating agents. The compound 2-acetoxyl-1-nitronaphthalene, found in fresh diesel particalates, is shown to hydrolyse during fractionation, thus introducing a note of caution into the use of such procedures.
Evaluation of Genotoxic and Mutagenic Activity of Organic Extracts from Drinking Water Sources

PubMed Central

Guan, Ying; Wang, Xiaodong; Wong, Minghung; Sun, Guoping; An, Taicheng; Guo, Jun

2017-01-01

An increasing number of industrial, agricultural and commercial chemicals in the aquatic environment lead to various deleterious effects on organisms, which is becoming a serious global health concern. In this study, the Ames test and SOS/umu test were conducted to investigate the potential genotoxicity and mutagenicity caused by organic extracts from drinking water sources. Organic content of source water was extracted with XAD-2 resin column and organic solvents. Four doses of the extract equivalent to 0.25, 0.5, 1 and 2L of source water were tested for toxicity. All the water samples were collected from six different locations in Guangdong province. The results of the Ames test and SOS/umu test showed that all the organic extracts from the water samples could induce different levels of DNA damage and mutagenic potentials at the dose of 2 L in the absence of S9 mix, which demonstrated the existence of genotoxicity and mutagenicity. Additionally, we found that Salmonella typhimurium strain TA98 was more sensitive for the mutagen. Correlation analysis between genotoxicity, Organochlorine Pesticides (OCPs) and Polycyclic Aromatic Hydrocarbons (PAHs) showed that most individual OCPs were frame shift toxicants in drinking water sources, and there was no correlation with total OCPs and PAHs. PMID:28125725
Chemical characterization and cytotoxic, genotoxic, and mutagenic properties of Baccharis trinervis (Lam, Persoon) from Colombia and Brazil.

PubMed

Jaramillo-García, Victoria; Trindade, Cristiano; Lima, Elisiane; Guecheva, Temenouga N; Villela, Izabel; Martinez-Lopez, Wilner; Corrêa, Dione S; Ferraz, Alexandre de B F; Moura, Sidnei; Sosa, Milton Quintana; Da Silva, Juliana; Henriques, João Antônio Pegas

2018-03-01

Baccharis trinervis (Lam, Persoon) leaves are used in the traditional medicine for the treatment of high fevers, edema, inflammation, sores and muscle cramps, snakebites and as antiseptic. To investigate the cytotoxic, genotoxic, and mutagenic effects of extracts and fractions of B. trinervis from Brazil and Colombia in Chinese Hamster Ovary (CHO) cells, and to examine the mutagenic activity in Salmonella typhimurium. Aqueous extracts (AE) of aerial parts of B. trinervis from Brazil (B) and Colombia (C) were fractioned in ethyl acetate fraction (EAF), butanol extract (BF), and aqueous residue fraction (ARF). Qualitative chemical screening and determination of total flavonoid content were made. Identification of chemical constituents was performed by High Performance Liquid Chromatography (HPLC) and High Resolution Mass Spectrometry (HRMS). For the in vitro tests, CHO cells were treated for 3h with extracts and fractions. The cytotoxic activity was evaluated by clonal survival and 3-(4.5-dimethylthiazole-2-yl)-2.5-biphenyl tetrazolium bromide reduction assay (MTT). Genotoxic and mutagenic effects were evaluated by the alkaline comet assay and Cytokinesis-blockage micronucleus test (CBMN), respectively. Additionally, Salmonella/microsome assay was carried out to determinate the mutagenic effects in EAF from Brazil and Colombia. Phytochemical analyses indicated the presence of saponins and flavonoids. AE and EAF were the samples with the highest quantity of total flavonoids. HPLC showed the presence of luteolin only in AEC, and caffeic acid, ellagic acid, rosmarinic acid, and rutin were identified in AEB and AEC (AEC>AEB). The HRMS in positive mode of EAFB and EAFC showed presence of two carboxylic acids, coumarin, and two terpenoids. In addition, were identified one terpenoid and two carboxylic acids in AE, BF and ARF of B. trinervis from both countries in negative mode. Dose-dependent cytotoxic effects were observed in CHO cells treated with B. trinervis extracts and fractions by using clonal survival and MTT at concentrations higher than 0.05mg/mL. All the extracts and fractions induced DNA strand breaks in CHO cells with dose-dependent response, mostly EAFB and EAFC. The EAF from Brazil and Colombia showed mutagenic effect at 0.5mg/mL, while the other fractions did not show a significant difference in relation to the control. No mutagenic effects were found in EAF from both countries by the Salmonella/microsome assay. Cytotoxic and genotoxic effects were demonstrated in all extracts and fractions used, although only EAF showed mutagenic effects by CBMN, but not by Salmonella/microsome assay. Our results suggest that flavonoids, phenylpropanoids, coumarins, and diterpenes may be responsible for the cytotoxic, genotoxic and mutagenic effects observed. Copyright © 2017 Elsevier B.V. All rights reserved.
The Tell-Tale Data: Virtual Whispering and Final Student Grades

ERIC Educational Resources Information Center

Cook, Susan; Germann, Clark

2010-01-01

Online classroom management issues pose new problems for the online instructor and pose seductive communicative options for students. This exploratory group of studies examined Blackboard/WEBCT[TM] data as collected for the course designer of an online course as possible indicators of "whispering" or backchanneling between students with…
Finite dimensional approximation of a class of constrained nonlinear optimal control problems

NASA Technical Reports Server (NTRS)

Gunzburger, Max D.; Hou, L. S.

1994-01-01

An abstract framework for the analysis and approximation of a class of nonlinear optimal control and optimization problems is constructed. Nonlinearities occur in both the objective functional and in the constraints. The framework includes an abstract nonlinear optimization problem posed on infinite dimensional spaces, and approximate problem posed on finite dimensional spaces, together with a number of hypotheses concerning the two problems. The framework is used to show that optimal solutions exist, to show that Lagrange multipliers may be used to enforce the constraints, to derive an optimality system from which optimal states and controls may be deduced, and to derive existence results and error estimates for solutions of the approximate problem. The abstract framework and the results derived from that framework are then applied to three concrete control or optimization problems and their approximation by finite element methods. The first involves the von Karman plate equations of nonlinear elasticity, the second, the Ginzburg-Landau equations of superconductivity, and the third, the Navier-Stokes equations for incompressible, viscous flows.
STRUCTURE-ACTIVITY RELATIONSHIPS (SARS) AMONG MUTAGENS AND CARCINOGENS: A REVIEW

EPA Science Inventory

The review is an introduction to methods for evaluating structure-activity relationships (SARs), and, in particular, to those methods that have been applied to study mutagenicity and carcinogenicity. A brief history and some background material on the earliest attempts to correla...
URINARY MUTAGENICITY AND COLORECTAL ADENOMA RISK

EPA Science Inventory

Abstract

We investigated urinary mutagenicity and colorectal adenoma risk in a clinic-based, case-control study of currently nonsmoking cases (n = 143) and controls (n = 156). Urinary organics were extracted by C18/methanol from 12-h overnight urine samples, and mutagenici...
THE SOURCES, FATE AND HAZARDS OF MUTAGENS IN SURFACE WATERS

EPA Science Inventory

A variety of industrial, domestic and agricultural wastes are discharged into rivers, lakes, streams, and estuaries. In some instances, these wastes contain substances that are capable I of permanently altering the genetic material of exposed organisms (i.e., they are mutagens). ...
Quantitative changes in endogenous DNA damage correlate with conazole mutagenicity and tumorigenicity.

EPA Science Inventory

The mouse liver tumorigenic conazolefungicides triadimefon and propiconazole have previously been shown to be in vivo mouse liver mutagens in the Big Blue" transgenic mutation assay when administered in feed at tumorigenic doses, whereas the nontumorigenic conazole myclobutanil w...
Declaring the Existence of Human Germ-Cell Mutagens

EPA Science Inventory

After more than 80 years of searching for human germ-cell mutagens, I think that sufficient evidence already exists for a number of agents to be so considered, and definitive confirmation seems imminent due to the application ofrecently developed genomic techniques. In preparatio...
Simulated space radiation-induced mutants in the mouse kidney display widespread genomic change

PubMed Central

Grygoryev, Dmytro; Lasarev, Michael; Ohlrich, Anna; Rwatambuga, Furaha A.; Johnson, Sorrel; Dan, Cristian; Eckelmann, Bradley; Hryciw, Gwen; Mao, Jian-Hua; Snijders, Antoine M.; Gauny, Stacey; Kronenberg, Amy

2017-01-01

Exposure to a small number of high-energy heavy charged particles (HZE ions), as found in the deep space environment, could significantly affect astronaut health following prolonged periods of space travel if these ions induce mutations and related cancers. In this study, we used an in vivo mutagenesis assay to define the mutagenic effects of accelerated 56Fe ions (1 GeV/amu, 151 keV/μm) in the mouse kidney epithelium exposed to doses ranging from 0.25 to 2.0 Gy. These doses represent fluences ranging from 1 to 8 particle traversals per cell nucleus. The Aprt locus, located on chromosome 8, was used to select induced and spontaneous mutants. To fully define the mutagenic effects, we used multiple endpoints including mutant frequencies, mutation spectrum for chromosome 8, translocations involving chromosome 8, and mutations affecting non-selected chromosomes. The results demonstrate mutagenic effects that often affect multiple chromosomes for all Fe ion doses tested. For comparison with the most abundant sparsely ionizing particle found in space, we also examined the mutagenic effects of high-energy protons (1 GeV, 0.24 keV/μm) at 0.5 and 1.0 Gy. Similar doses of protons were not as mutagenic as Fe ions for many assays, though genomic effects were detected in Aprt mutants at these doses. Considered as a whole, the data demonstrate that Fe ions are highly mutagenic at the low doses and fluences of relevance to human spaceflight, and that cells with considerable genomic mutations are readily induced by these exposures and persist in the kidney epithelium. The level of genomic change produced by low fluence exposure to heavy ions is reminiscent of the extensive rearrangements seen in tumor genomes suggesting a potential initiation step in radiation carcinogenesis. PMID:28683078
Simulated space radiation-induced mutants in the mouse kidney display widespread genomic change.

PubMed

Turker, Mitchell S; Grygoryev, Dmytro; Lasarev, Michael; Ohlrich, Anna; Rwatambuga, Furaha A; Johnson, Sorrel; Dan, Cristian; Eckelmann, Bradley; Hryciw, Gwen; Mao, Jian-Hua; Snijders, Antoine M; Gauny, Stacey; Kronenberg, Amy

2017-01-01

Exposure to a small number of high-energy heavy charged particles (HZE ions), as found in the deep space environment, could significantly affect astronaut health following prolonged periods of space travel if these ions induce mutations and related cancers. In this study, we used an in vivo mutagenesis assay to define the mutagenic effects of accelerated 56Fe ions (1 GeV/amu, 151 keV/μm) in the mouse kidney epithelium exposed to doses ranging from 0.25 to 2.0 Gy. These doses represent fluences ranging from 1 to 8 particle traversals per cell nucleus. The Aprt locus, located on chromosome 8, was used to select induced and spontaneous mutants. To fully define the mutagenic effects, we used multiple endpoints including mutant frequencies, mutation spectrum for chromosome 8, translocations involving chromosome 8, and mutations affecting non-selected chromosomes. The results demonstrate mutagenic effects that often affect multiple chromosomes for all Fe ion doses tested. For comparison with the most abundant sparsely ionizing particle found in space, we also examined the mutagenic effects of high-energy protons (1 GeV, 0.24 keV/μm) at 0.5 and 1.0 Gy. Similar doses of protons were not as mutagenic as Fe ions for many assays, though genomic effects were detected in Aprt mutants at these doses. Considered as a whole, the data demonstrate that Fe ions are highly mutagenic at the low doses and fluences of relevance to human spaceflight, and that cells with considerable genomic mutations are readily induced by these exposures and persist in the kidney epithelium. The level of genomic change produced by low fluence exposure to heavy ions is reminiscent of the extensive rearrangements seen in tumor genomes suggesting a potential initiation step in radiation carcinogenesis.
Quantitative mammalian cell genetic toxicology: study of the cytotoxicity and mutagenicity of 70 individual environmental agents related to energy technologies and 3 subfractions of a crude synthetic oil in the CHO/HGPRT system. [Hamsters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsie, A W; ,; Neill, J P

1978-01-01

Conditions necessary for quantifying mutation-induction to 6-thioguanine resistance, which selects for >98% mutants deficient in the activity of hypoxanthine-guanine phosphoribosyl transferase (HGPRT) in a near-diploid Chinese hamster ovary (CHO) cell line, referred to as CHO/HGPRT system, have been defined. Employing this mutation assay, we have determined the mutagenicity of diversified agents including 11 direct-acting alkylating agents, 16 nitrosamines, 10 heterocyclic nitrogen mustards, 15 metallic compounds, 5 quinolines, 5 aromatic amines, 27 polycyclic hydrocarbons, 13 miscellaneous chemicals, 7 ionizing and non-ionizing physical agents. The direct-acting carcinogen N-methyl-N'-nitro-N-nitrosoguanidine is mutagenic while its noncarcinogenic analogue N-methyl-N'-nitro-N-nitroguanidine is not. Coupled with the rat livermore » S/sub 9/-activation system, procarcinogens such as nitrosopyrrolidine, benzo(a)pyrene, and 2-acetylaminofluorene are mutagenic while their analogues 2,5-dimethylnitrosopyrrolidine, pyrene and fluorene are not. The assay appears to be applicable for monitoring the genetic toxicity of crude organic mixtures in addition to diverse individual chemical and physical agents. The quantitative nature of the assay enables a study of EMS exposure dose: the mutagenic potential of EMS can be described as 310 x 10/sup -6/ mutants (cell mg ml/sup -1/ h)./sup -1/ It is also feasible to expand the CHO/HGPRT system for quantifying cytotoxicity and mutagenicity to determination of chromosomal aberrations and sister chromatid exchanges in cells treated under identical conditions which allows a simultaneous study of these four distinctive biological effects.« less

Genotoxic and mutagenic properties of Bauhinia platypetala extract, a traditional Brazilian medicinal plant.

PubMed

Santos, Francisco José Borges Dos; Moura, Dinara Jaqueline; Péres, Valéria Flores; Sperotto, Angelo Regis de Moura; Caramão, Elina Bastos; Cavalcante, Ana Amélia de Carvalho Melo; Saffi, Jenifer

2012-12-18

Bauhinia platypetala Burch. is a traditionally used Brazilian medicinal plant, although no evidence in the literature substantiates the safety of its use. The aim of this study was to investigate the safety of the ethanolic extract and the ethereal fraction of B. platypetala leaves. The identification of chemical compounds from the B. platypetala ethanolic extract and its ethereal fraction was performed by GC/MS and ESI-MS/MS. The plant's toxicological, cytotoxic, mutagenic and genotoxic properties were determined in Saccharomyces cerevisiae strains and V79 cell culture by survival assays and comet assay. The major compound identified in the B. platypetala ethanolic extract is palmitic acid, kaempferitirin and quercitrin, while the B. platypetala ethereal fraction was found to be rich in phytol, gamma-sitosterol and vitamin E. Moreover, the results indicated that the B. platypetala ethanolic extract has an anti-oxidative effect against H(2)O(2) in yeast. In addition, the B. platypetala ethanolic extract did not induce mutagenic effects on the S. cerevisiae N123 strain, but the ethereal fraction of B. platypetala at higher concentrations (250-500 μg/mL) induced cytotoxicity and mutagenicity. A slight cytotoxic effect was observed in mammalian V79 cells; however, both the B. platypetala ethanolic extract and its ethereal fraction were able to induce DNA strand breaks in V79 cells, as detected by the alkaline comet assay. The B. platypetala ethanolic extract has antioxidant action and showed absence of mutagenic effects in yeast S. cerevisiae. On the other hand B. platypetala ethereal fraction is mutagenic and does not show antioxidant activity in yeast. In mammalian cells B. platypetala ethanolic extract and it's ethereal fraction induce cyotoxic and genotoxic action. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
In vitro genotoxicity of neutral red after photo-activation and metabolic activation in the Ames test, the micronucleus test and the comet assay.

PubMed

Guérard, Melanie; Zeller, Andreas; Singer, Thomas; Gocke, Elmar

2012-07-04

Neutral red (Nr) is relatively non-toxic and is widely used as indicator dye in many biological test systems. It absorbs visible light and is known to act as a photosensitizer, involving the generation of reactive oxygen species (type-I reaction) and singlet oxygen (type-II reaction). The mutagenicity of Nr was determined in the Ames test (with Salmonella typhimurium strains TA1535, TA97, TA98, TA98NR, TA100, and TA102) with and without metabolic activation, and with and without photo-activation on agar plates. Similarly to the situation following metabolic activation, photo-mutagenicity of Nr was seen with all Salmonella strains tested, albeit with different effects between these strains. To our knowledge, Nr is the only photo-mutagen showing such a broad action. Since the effects are also observed in strains not known to be responsive to ROS, this indicates that ROS production is not the sole mode of action that leads to photo-genotoxicity. The reactive species produced by irradiation are short-lived as pre-irradiation of an Nr solution did not produce mutagenic effects when added to the bacteria. In addition, mutagenicity in TA98 following irradiation was stronger than in the nitroreductase-deficient strain TA98NR, indicating that nitro derivatives that are transformed by bacterial nitroreductase to hydroxylamines appear to play a role in the photo-mutagenicity of Nr. Photo-genotoxicity of Nr was further investigated in the comet assay and micronucleus test in L5178Y cells. Concentration-dependent increases in primary DNA damage and in the frequency of micronuclei were observed after irradiation. Copyright © 2012 Elsevier B.V. All rights reserved.
Atypical Role for PhoU in Mutagenic Break Repair under Stress in Escherichia coli

PubMed Central

Aponyi, Ildiko; Vera Cruz, Diana; Ray, Mellanie P.; Rosenberg, Susan M.

2015-01-01

Mechanisms of mutagenesis activated by stress responses drive pathogen/host adaptation, antibiotic and anti-fungal-drug resistance, and perhaps much of evolution generally. In Escherichia coli, repair of double-strand breaks (DSBs) by homologous recombination is high fidelity in unstressed cells, but switches to a mutagenic mode using error-prone DNA polymerases when the both the SOS and general (σS) stress responses are activated. Additionally, the σE response promotes spontaneous DNA breakage that leads to mutagenic break repair (MBR). We identified the regulatory protein PhoU in a genetic screen for functions required for MBR. PhoU negatively regulates the phosphate-transport and utilization (Pho) regulon when phosphate is in excess, including the PstB and PstC subunits of the phosphate-specific ABC transporter PstSCAB. Here, we characterize the PhoU mutation-promoting role. First, some mutations that affect phosphate transport and Pho transcriptional regulation decrease mutagenesis. Second, the mutagenesis and regulon-expression phenotypes do not correspond, revealing an apparent new function(s) for PhoU. Third, the PhoU mutagenic role is not via activation of the σS, SOS or σE responses, because mutations (or DSBs) that restore mutagenesis to cells defective in these stress responses do not restore mutagenesis to phoU cells. Fourth, the mutagenesis defect in phoU-mutant cells is partially restored by deletion of arcA, a gene normally repressed by PhoU, implying that a gene(s) repressed by ArcA promotes mutagenic break repair. The data show a new role for PhoU in regulation, and a new regulatory branch of the stress-response signaling web that activates mutagenic break repair in E. coli. PMID:25961709
The nucleolus is well-posed

NASA Astrophysics Data System (ADS)

Fragnelli, Vito; Patrone, Fioravante; Torre, Anna

2006-02-01

The lexicographic order is not representable by a real-valued function, contrary to many other orders or preorders. So, standard tools and results for well-posed minimum problems cannot be used. We prove that under suitable hypotheses it is however possible to guarantee the well-posedness of a lexicographic minimum over a compact or convex set. This result allows us to prove that some game theoretical solution concepts, based on lexicographic order are well-posed: in particular, this is true for the nucleolus.
The Circle of Apollonius and Its Applications in Introductory Physics

NASA Astrophysics Data System (ADS)

Partensky, Michael B.

2008-02-01

The circle of Apollonius is named after the ancient geometrician Apollonius of Perga. This beautiful geometric construct can be helpful when solving some general problems of geometry and mathematical physics, optics, and electricity. Here we discuss two of its applications: localizing an object in space and calculating electric fields. First, we pose an entertaining localization problem to trigger students' interest in the subject. Analyzing this problem, we introduce the circle of Apollonius and show that this geometric technique helps solve the problem in an elegant and intuitive manner. Then we switch to seemingly unrelated problems of calculating the electric fields. We show that the zero equipotential line for two unlike charges is the Apollonius circle for these two charges and use this discovery to find the electric field of a charge positioned near a grounded conductive sphere. Finally, we pose some questions for further examination.
Is the DPT tautomerization of the long A·G Watson-Crick DNA base mispair a source of the adenine and guanine mutagenic tautomers? A QM and QTAIM response to the biologically important question.

PubMed

Brovarets', Ol'ha O; Zhurakivsky, Roman O; Hovorun, Dmytro M

2014-03-05

Herein, we first address the question posed in the title by establishing the tautomerization trajectory via the double proton transfer of the adenine·guanine (A·G) DNA base mispair formed by the canonical tautomers of the A and G bases into the A*·G* DNA base mispair, involving mutagenic tautomers, with the use of the quantum-mechanical calculations and quantum theory of atoms in molecules (QTAIM). It was detected that the A·G ↔ A*·G* tautomerization proceeds through the asynchronous concerted mechanism. It was revealed that the A·G base mispair is stabilized by the N6H···O6 (5.68) and N1H···N1 (6.51) hydrogen bonds (H-bonds) and the N2H···HC2 dihydrogen bond (DH-bond) (0.68 kcal·mol(-1) ), whereas the A*·G* base mispair-by the O6H···N6 (10.88), N1H···N1 (7.01) and C2H···N2 H-bonds (0.42 kcal·mol(-1) ). The N2H···HC2 DH-bond smoothly and without bifurcation transforms into the C2H···N2 H-bond at the IRC = -10.07 Bohr in the course of the A·G ↔ A*·G* tautomerization. Using the sweeps of the energies of the intermolecular H-bonds, it was observed that the N6H···O6 H-bond is anticooperative to the two others-N1H···N1 and N2H···HC2 in the A·G base mispair, while the latters are significantly cooperative, mutually strengthening each other. In opposite, all three O6H···N6, N1H···N1, and C2H···N2 H-bonds are cooperative in the A*·G* base mispair. All in all, we established the dynamical instability of the А*·G* base mispair with a short lifetime (4.83·10(-14) s), enabling it not to be deemed feasible source of the A* and G* mutagenic tautomers of the DNA bases. The small lifetime of the А*·G* base mispair is predetermined by the negative value of the Gibbs free energy for the A*·G* → A·G transition. Moreover, all of the six low-frequency intermolecular vibrations cannot develop during this lifetime that additionally confirms the aforementioned results. Thus, the A*·G* base mispair cannot be considered as a source of the mutagenic tautomers of the DNA bases, as the A·G base mispair dissociates during DNA replication exceptionally into the A and G monomers in the canonical tautomeric form. Copyright © 2013 Wiley Periodicals, Inc.
MUTAGENIC PROPERTIES OF RIVER WATERS FLOWING THROUGH BIG CITY AREAS IN NORTH AMERICA

EPA Science Inventory

The hanging technique using Blue rayon, which specifically adsorbs mutagens with multicyclic planer structures, has advantages over the conventional method of bringing-large volumes of water back to the laboratory for extraction. Therefore, the analysis of many samples from remot...
1-CHLOROMETHYLPYRENE; A SKIN SENSITIZER AND GENOTOXIN

EPA Science Inventory

1-Chloromethylpyrene has been evaluated as a model mutagen and toxin related to the ultimate electrophiles derived from BaP and 1-Nitropyren. t was mutagenic to salmonella 6100 picograms/plate) and exceptionally reactive to DNA when assessed by the postlabeling assay. MP was inac...
GENOTOXICITY STUDIES OF SODIUM DICHLOROACETATE AND SODIUM TRICHLOROACETATE

EPA Science Inventory

The genotoxic properties of sodium dichloroacetate (DCA) and sodium trichloroacetate (TCA)were evaluated in several short-term in vitro and in vivo assays. Neither compound was mutagenic in tester strain TA102 in the Salmonella mutagenicity assay. Both DCA and TCA were weak induc...
REPRODUCTIVE EFFECTS ASSESSMENT GROUP'S REVIEW OF THE MUTAGENICITY OF VINYLIDENE CHLORIDE

EPA Science Inventory

A large number of studies indicate that vinylidene chloride is mutagenic to bacteria and that this activity is largely dependent on microsomal activation. Vinylidene chloride was reported to produce positive results for gene reversion and conversion in yeast, which was also depen...
Predictive Models for Carcinogenicity and Mutagenicity: Frameworks, State-of-the-Art, and Perspectives

EPA Science Inventory

Mutagenicity and carcinogenicity are endpoints of major environmental and regulatory concern. These endpoints are also important targets for development of alternative methods for screening and prediction due to the large number of chemicals of potential concern and the tremendou...
RESIDUAL MUTAGENICITY OF THE ALASKAN OIL SPILL ORGANICS

EPA Science Inventory

RESIDUAL MUTAGENICITY OF THE ALASKAN OIL SPILL ORGANICS. L.D.

The Exxon Valdez, on March 24, 1989, spilled approximately eleven million gallons of Prudhoe Bay crude oil into the waters of Prince William Sound. Approximately 300 miles of
contaminated beach are potential...
IN VITRO AND IN VIVO MUTAGENICITY STUDIES OF ENVIRONMENTAL CHEMICALS

EPA Science Inventory

The objectives of this project were to evaluate the mutagenicity of various compounds, mostly pesticides, using microbial and mammalian cell in vitro techniques, as well as in vivo techniques in Drosophila and mice, and to further develop and refine these procedures for applicati...
A REVIEW OF THE RODENT CARCINOGENICTY AND MUTAGENICITY OF AMBIENT AIR

EPA Science Inventory

This is a review of the information known about the carcinogenicity and mutagenicity of urban outdoor air including volatile pollutants and particulate organic material. The editors of Mutation Research decided to create a second special review volume on what is known about ...
Predictive Models for Carcinogenicity and Mutagenicity: Frameworks,State-of-the-Art, and Perspectives

EPA Science Inventory

Mutagenicity and carcinogenicity are endpoints of major environmental and regulatory concern. These endpoints are also important targets for development of alternative methods for screening and prediction due to the large number of chemicals of potential concern and the tremendou...
PUBLIC SOURCES OF MUTAGENICITY AND CARCINOGENICITY DATA: USE IN STRUCTURE-ACTIVITY RELATIONSHIP MODELS

EPA Science Inventory

No Abstract - first paragraph of INTRODUCTION

Publicly supported compilations of mutagenicity and carcinogenicity data are available
for a significant number and variety of environmental and industrial chemicals and, to a lesser
extent, pharmaceutical chemicals. T...
Mutagenic atmospheres resulting from the photooxidation of aromatic hydrocarbon and NOx mixtures

EPA Science Inventory

Although many volatile organic compounds (VOCs) are regulated to limit air pollution and the consequent health effects, the photooxidation products generally are not. Thus, we examined the mutagenicity in Salmonella TA100 of photochemical atmospheres generated in a steady-state a...
Carcinogenicity and Mutagenicity Data: New Initiatives to Improve Access and Utility for Modeling

EPA Science Inventory

Currents models for prediction of chemical carcinogenicity and mutagenicity rely upon a relatively small number of publicly available data resources, where the data being modeled are highly summarized and aggregated representations of the actual experimental results. A number of...
dbAMEPNI: a database of alanine mutagenic effects for protein–nucleic acid interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Ling; Xiong, Yi; Gao, Hongyun

Protein–nucleic acid interactions play essential roles in various biological activities such as gene regulation, transcription, DNA repair and DNA packaging. Understanding the effects of amino acid substitutions on protein–nucleic acid binding affinities can help elucidate the molecular mechanism of protein–nucleic acid recognition. Until now, no comprehensive and updated database of quantitative binding data on alanine mutagenic effects for protein–nucleic acid interactions is publicly accessible. Thus, we developed a new database of Alanine Mutagenic Effects for Protein-Nucleic Acid Interactions (dbAMEPNI). dbAMEPNI is a manually curated, literature-derived database, comprising over 577 alanine mutagenic data with experimentally determined binding affinities for protein–nucleic acidmore » complexes. Here, it contains several important parameters, such as dissociation constant (Kd), Gibbs free energy change (ΔΔG), experimental conditions and structural parameters of mutant residues. In addition, the database provides an extended dataset of 282 single alanine mutations with only qualitative data (or descriptive effects) of thermodynamic information.« less
Mutagenicity and cytoxicity of irradiated foods and food components*

PubMed Central

Schubert, Jack

1969-01-01

The preservation of foods by treatment with ionizing radiation can significantly increase the world's food resources by reducing spoilage and waste. However, irradiation can bring about chemical transformations in food and food components resulting in the formation of potential mutagens, particularly hydrogen peroxide and various organic peroxides. In order to evaluate the safety of irradiated foods for general consumption by the public, and, indeed, the safety of all foods subjected to environmental factors such as food additives, pesticides, drugs, air and water pollutants, etc., it is necessary to supplement the usual feeding tests with procedures designed to detect all classes of genetic damage. This article includes a comprehensive critical review of (1) the experimental evidence relating to the presence of mutagenic and cytotoxic agents in irradiated media, as detected by their effects on mammalian and non-mammalian cells; (2) the chemical changes produced in irradiated media, especially those which produce known mutagenic substances; and (3) new and convenient in vivo methods for the detection and evaluation of genetic damage in mammals. PMID:4908553

Mutagenicity testing with transgenic mice. Part I: Comparison with the mouse bone marrow micronucleus test

PubMed Central

Wahnschaffe, U; Bitsch, A; Kielhorn, J; Mangelsdorf, I

2005-01-01

As part of a larger literature study on transgenic animals in mutagenicity testing, test results from the transgenic mutagenicity assays (lacI model; commercially available as the Big Blue® mouse, and the lacZ model; commercially available as the Muta™Mouse), were compared with the results on the same substances in the more traditional mouse bone marrow micronucleus test. 39 substances were found which had been tested in the micronucleus assay and in the above transgenic mouse systems. Although, the transgenic animal mutation assay is not directly comparable with the micronucleus test, because different genetic endpoints are examined: chromosome aberration versus gene mutation, the results for the majority of substances were in agreement. Both test systems, the transgenic mouse assay and the mouse bone marrow micronucleus test, have advantages and they complement each other. However, the transgenic animal assay has some distinct advantages over the micronucleus test: it is not restricted to one target organ and detects systemic as well as local mutagenic effects. PMID:15655069
dbAMEPNI: a database of alanine mutagenic effects for protein–nucleic acid interactions

DOE PAGES

Liu, Ling; Xiong, Yi; Gao, Hongyun; ...

2018-04-02

Protein–nucleic acid interactions play essential roles in various biological activities such as gene regulation, transcription, DNA repair and DNA packaging. Understanding the effects of amino acid substitutions on protein–nucleic acid binding affinities can help elucidate the molecular mechanism of protein–nucleic acid recognition. Until now, no comprehensive and updated database of quantitative binding data on alanine mutagenic effects for protein–nucleic acid interactions is publicly accessible. Thus, we developed a new database of Alanine Mutagenic Effects for Protein-Nucleic Acid Interactions (dbAMEPNI). dbAMEPNI is a manually curated, literature-derived database, comprising over 577 alanine mutagenic data with experimentally determined binding affinities for protein–nucleic acidmore » complexes. Here, it contains several important parameters, such as dissociation constant (Kd), Gibbs free energy change (ΔΔG), experimental conditions and structural parameters of mutant residues. In addition, the database provides an extended dataset of 282 single alanine mutations with only qualitative data (or descriptive effects) of thermodynamic information.« less
Identification of potential fish carcinogens in sediment from Hamilton Harbour, Ontario, Canada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balch, G.C.; Metcalfe, C.D.; Huestis, S.Y.

1995-01-01

A carcinogenicity- and mutagenicity-directed fractionation approach was used to identify the carcinogenic compounds in contaminated sediments that are putatively responsible for the high prevalence of tumors in bottom-dwelling fish from Hamilton Harbour, Ontario. Mutagenic activity was detected with Ames tester strains (TA98, TA100) in relatively nonpolar fractions of sediment extract containing PAHs and nitrogen-containing aromatic compounds (NCACs). These fractions were also carcinogenic in an in vivo carcinogenicity bioassay with rainbow trout (Oncorhynchus mykiss). When a more polar extract fraction was tested for mutagenicity and carcinogenicity, weak mutagenic activity was detected with an O-acetyltransferase-enriched Ames tester strain (YG1024), and weak carcinogenicmore » activity was detected in the rainbow trout assay. These data indicate that PAHs in contaminated Hamilton Harbour sediments are potent fish carcinogens, but it is also evident that other organic compounds in the sediment, such as NCACs and nitroarenes, may contribute to carcinogenicity.« less
Sister chromatid exchanges induced by inhaled anesthetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

White,A.E.; Takehisa, S.; Eger II, E.I.

1970-05-01

There is sufficient evidence that anesthetics may cause cancer to justify a test of their carcinogenic potential. Baden et al., using the Ames test, a rapid and inexpensive genetic indicator of carcinogenicity, have shown that among currently used anesthetics fluorxene alone caused bacterial mutations. The authors used the sister chromatid exchange (SCE) technique, another rapid assay of mutagenic-carcinogenic potential. The frequency of sister chromatid exchanges in Chinese hamster ovary cells increases when the cell cultures are exposed to mutagen-carcinogens, particulary in the presence of a metabolic activating system. With this test system a one-hour exposure to 1 MAC nitrous oxide,more » diethyl ether, trichloroethylene, halothane, enflurane, isoflurane, methoxyflurane, or chloroform did not increase SCE values. Divinyl ether, fluroxene and ethyl vinyl ether increased SCE values in the same circumstances. Results of this study of mammalian cells suggest that no currently used anesthetic is a mutagen-carcinogen. The results also suggest that anesthetics containing a vinyl moiety may be mutagen-carcinogens.« less
Oxygen induces mutation in a strict anaerobe, Prevotella melaninogenica.

PubMed

Takumi, Shota; Komatsu, Masaharu; Aoyama, Kohji; Watanabe, Kunitomo; Takeuchi, Toru

2008-05-15

Strict anaerobes are highly sensitive to oxygen, but the mutagenicity of oxygen in strict anaerobes has not been well understood. Prevotella melaninogenica, a strict anaerobe, is susceptible to oxygen and shows an increase in oxidative DNA damage upon exposure to oxygen. In this study, we have investigated the mutagenicity of oxygen and the types of mutations induced by oxygen. Exposure to oxygen decreased cell survival and increased the levels of 8-oxo-deoxyguanosine (8-oxodG). The frequency of rifampicin-resistant mutants was markedly increased after exposure to oxygen. After sequencing a 254-bp fragment of the rpoB gene, which encodes the beta subunit of bacterial RNA polymerase, a target molecule of rifampicin, we found that most mutants induced by oxygen had GC to TA transversions, a signature of 8-oxodG. In addition, all detected single-nucleotide changes would lead to amino acid changes that confer rifampicin resistance. These results indicate that oxygen is mutagenic in a strict anaerobe, P. melaninogenica, and its mutagenic characteristics could be analyzed with this experimental system.
Evaluation of the mutagenicity of alkylating agents, methylnitrosourea and temozolomide, using the rat Pig-a assay with total red blood cells or reticulocytes.

PubMed

Muto, Shigeharu; Yamada, Katsuya; Kato, Tatsuya; Ando, Masamitsu; Inoue, Yoshimi; Iwase, Yumiko; Uno, Yoshifumi

2016-11-15

A collaborative study of the endogenous phosphatidylinositol glycan class A (Pig-a) gene mutation assay was conducted by the Japanese Environmental Mutagen Society/Mammalian Mutagenicity Study Group with a single-dosing regimen of test chemicals administered to male rats. As a part of the study, two DNA alkylating agents, methylnitrosourea (MNU) and temozolomide (TMZ), were dosed by single oral gavage at 25, 50, and 100mg/kg body weight. Pig-a mutant analysis of total red blood cells (RBCs; RBC Pig-a assay) and reticulocytes (RETs; PIGRET assay) was performed on Days 8, 15 and 29 after the administration. Both chemicals increased Pig-a mutants among RBCs and RETs with dose dependency on all days examined. The mutant frequencies were higher among RETs compared with RBCs, indicating that the PIGRET assay could detect mutagenicity more sensitively than the RBC Pig-a assay after a single dose of test chemicals. Copyright © 2016 Elsevier B.V. All rights reserved.
Point Cloud Based Relative Pose Estimation of a Satellite in Close Range

PubMed Central

Liu, Lujiang; Zhao, Gaopeng; Bo, Yuming

2016-01-01

Determination of the relative pose of satellites is essential in space rendezvous operations and on-orbit servicing missions. The key problems are the adoption of suitable sensor on board of a chaser and efficient techniques for pose estimation. This paper aims to estimate the pose of a target satellite in close range on the basis of its known model by using point cloud data generated by a flash LIDAR sensor. A novel model based pose estimation method is proposed; it includes a fast and reliable pose initial acquisition method based on global optimal searching by processing the dense point cloud data directly, and a pose tracking method based on Iterative Closest Point algorithm. Also, a simulation system is presented in this paper in order to evaluate the performance of the sensor and generate simulated sensor point cloud data. It also provides truth pose of the test target so that the pose estimation error can be quantified. To investigate the effectiveness of the proposed approach and achievable pose accuracy, numerical simulation experiments are performed; results demonstrate algorithm capability of operating with point cloud directly and large pose variations. Also, a field testing experiment is conducted and results show that the proposed method is effective. PMID:27271633
Mutagenicity of p-aminophenol in E. coli WP2uvrA/pKM101 and its relevance to oxidative DNA damage.

PubMed

Yoshida, R; Oikawa, S; Ogawa, Y; Miyakoshi, Y; Ooida, M; Asanuma, K; Shimizu, H

1998-07-08

It was recently reported that p-aminophenol (p-AP) induces DNA cleavage in mouse lymphoma cells, CHO cells and human lymphoblastoid cells. The mutagenicity of p-AP has not, however, been detected by reverse mutation assays. The purpose of this study was to assess the mutagenicity of p-AP by reverse mutation assay using Escherichia coli WP2uvrA/pKM101, which has a spectrum for detecting mutations different from those of other strains in the family with an AT base pair at the mutation site and has higher sensitivity to certain oxidative mutagens as compared to other strains. We found that p-AP was mutagenic to E. coli WP2uvrA/pKM101. The mutagenic activity of this compound was suppressed with the addition of dimethylsulfoxide or catalase, suggesting the involvement of active oxygen species in the mutagenic process induced by p-AP. To further elucidate the underlying mechanism, we used isolated DNA for the following experiments. It was revealed, by gel electrophoretic analysis, that p-AP induced DNA cleavage in the presence of Fe(III). However, p-AP alone did not induce this cleavage. Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine by p-AP in calf thymus DNA was also detected in the presence of Fe(III) by HPLC with an electrochemical detector. ESR-spin trapping experiments using DMPO detected the production of hydroxyl radical (.OH) in the solution of p-AP with Fe(III). Both p-AP mediated DNA damages and .OH production by p-AP in the presence of Fe(III) were completely inhibited by .OH scavengers (ethanol, mannitol, sodium formate, dimethylsulfoxide) and catalase. These results suggest that .OH derived from the reaction between H2O2 and Fe(III) (Fenton reaction) participates in the oxidative DNA damage. Accordingly, the same mechanism might be working in E. coli WP2uvrA/pKM101 during induction of the mutation by p-AP.
Bed Bug Epidemic: A Challenge to Public Health

ERIC Educational Resources Information Center

Ratnapradipa, Dhitinut; Ritzel, Dale O.; Haramis, Linn D.; Bliss, Kadi R.

2011-01-01

In recent years, reported cases of bed bug infestations in the U.S. and throughout the world have escalated dramatically, posing a global public health problem. Although bed bugs are not known to transmit disease to humans, they pose both direct and indirect public health challenges in terms of health effects, treatment, cost, and resource…
SMEs and their E-Commerce: Implications for Training in Wellington, New Zealand

ERIC Educational Resources Information Center

Beal, Tim; Abdullah, Moha Asri

2005-01-01

One of the greatest challenges facing traditional small and medium-sized enterprises (SMEs) throughout the world is that posed by the Internet. While the Internet offers great potential to SMEs, from improving and cheapening production processes through to reaching global customers, it also poses great problems. SMEs' resources, human and…
Effect of frequency-doubling pulse Nd:YAG laser on microbial mutation

NASA Astrophysics Data System (ADS)

Zhao, Yansheng; Wang, Luyan; Zheng, Heng; Yin, Hongping; Chen, Xiangdong; Tan, Zheng; Wu, Wutong

1999-09-01

We are going to report the mutagenic effect of frequency-doubling pulse Nd:YAG laser (532 nm) on microbe. After irradiation with pulse laser, mutants of abscisic acid producing strains and erythromycin producing strains were obtained, one of which could produce 62.1% and 57% more products than control, respectively. In the study of mutagenization of Spirulina platensis caused by pulse laser, we selected a high photosynthetic strains, with improved productivity of protein and exocellular ploysaccharides of 12% and 246%, respectively. The experimental results indicate that frequency-doubling pulse laser (532 nm) is a potential new type of physical mutagenic factor.
MUTAGENICITY OF NITRITE-TREATED AQUEOUS EXTRACT OF 'PIPER BETLE'; L

EPA Science Inventory

Betel quid is chewed as a masticatory material by people in certain areas of Asia. The quid chewing has been related to oral cancer by epidemiological study. The mutagenic components in the aqueous extracts of betel quid ingredients were studied. Only nitrite-treated aqueous extr...
MUTAGENICITY AND CARCINOGENICITY ASSESSMENT OF 1,3-BUTADIENE. REVIEW DRAFT

EPA Science Inventory

The Mutagenicity and Carcinogenicity Assessment of 1,3-Butadiene was prepared to serve as a source document for Agency-wide use. In the development of this assessment document, the scientific literature has been inventoried, key studies have been evaluated, and the summary and co...
EFFECT OF LAND TREATMENT ON THE MUTAGENICITY OF MILWAUKEE HARBOR SEDIMENT [POSTER PRESENTATION

EPA Science Inventory

Sediment from the Milwaukee harbor is known to be contaminated with PAHs and PCBs. A pilot-scale study was conducted to evaluate the potential of land treatment to detoxify these contaminants, as determined by several chemical and biological endpoints, including mutagenicity. T...
Carcinogens, Teratogens and Mutagens: Their Impact on Occupational Health, Particularly for Women in Veterinary Medicine.

ERIC Educational Resources Information Center

Milligan, J. E.; And Others

1983-01-01

Pregnant women, especially those working in veterinary medicine, face occupational health/disease risks from mutagens, teratogens, and carcinogens. These hazards can be placed into three categories: physical, chemical, and biological. Each of these hazards is discussed with examples. (Author/JN)
OVERVIEW OF THE MUTAGENICITY OF URBAN AIR

EPA Science Inventory

For the past 25 years, there has been great interest in the mutagenicity and carcinogenicity of ambient air and in the sources of those genotoxicants. Prior to the 1980's, the evaluation of airborne toxicants was done on a pollutant-by-pollutant basis. However, the assessment of ...
Health Effects of Soy-Biodiesel Emissions: Bioassay-Directed Fractionation for Mutagenicity*

EPA Science Inventory

BACKGROUND:Soy biodiesel is the predominant biodiesel used in the U.S., but there is little understanding of the classes of chemicals responsible for the mutagenicity of the emissions.OBJECTIVE: We determined some of the chemical classes responsible for various categories of mut...
Reproductive Effects Assessment Group's Report on the Mutagenicity of Inorganic Arsenic

EPA Science Inventory

Various inorganic compounds of arsenic have been tested for mutagenicity in a variety of test systems ranging in complexity from bacteria to peripheral lymphocytes of exposed human beings. Although a great deal of the data are contradictory, the weight of evidence supports the fo...
Evaluation of an Air Quality Health Index for Predicting the Mutagenicity of Simulated Atmospheres

EPA Science Inventory

No study has evaluated the mutagenicity of atmospheres with a calculated air quality health index (AQHI). Thus, we generated in a UV-light-containing reaction chamber two simulated atmospheres (SAs) with similar AQHIs but different proportions of criteria pollutants and evaluated...
Plant composition, pharmacological properties and mutagenic evaluation of a commercial Zulu herbal mixture: Imbiza ephuzwato.

PubMed

Ndhlala, A R; Finnie, J F; Van Staden, J

2011-01-27

Imbiza ephuzwato is a traditional herbal tonic made from a mixture of extracts of roots, bulbs, rhizomes and leaves of 21 medicinal plants and is used in traditional medicine as a multipurpose remedy. To compile and investigate the bioactivity and mutagenic effects of extracts of the 21 plant species used in the preparation of Imbiza ephuzwato herbal tonic. The 21 plant species used to make Imbiza ephuzwato herbal mixture were each investigated for their pharmacological properties. Petroleum ether (PE), dichloromethane (DCM), 80% ethanol (EtOH) and water extracts of the 21 plants were evaluated against two gram-positive, two gram-negative bacteria and a fungus Candida albicans. The extracts were also evaluated for their inhibitory effects against cyclooxygenase (COX-1 and -2) and acetylcholinesterase AChE enzymes. Mutagenic effects of the water extracts were evaluated using the Ames test. Gunnera perpensa and Rubia cordifolia were the only plant species used to manufacture Imbiza ephuzwato that had water extracts which showed good antibacterial activity. The extracts of G. perpensa (EtOH), Hypericum aethiopicum (DCM) and Urginea physodes (EtOH) showed the best antifungal activity. The water extracts of H. aethiopicum, G. perpensa, Drimia robusta, Vitellariopsis marginata, Scadoxus puniceus and Momordica balsamina showed percentage inhibition of COX-1 that was over 70%. For COX-2 enzyme, the water extracts of G. perpensa, Cyrtanthus obliquus, M. balsamina and Tetradenia riparia exhibited inhibitory activity above 70%. Water extracts of G. perpensa, C. obliquus, V. marginata, Asclepias fruticosa and Watsonia densiflora showed good AChE inhibitory activity (>80%). The Ames test results revealed that all the water extracts of the 21 plant species used to make Imbiza ephuzwato were non-mutagenic towards the Salmonella typhimurium TA98 strain for the assay with and without S9 metabolic activation. In contrast, Imbiza ephuzwato showed mutagenic effects after exposure to S9 enzyme mixture. The observed activities of some plant extracts, if supported by other confirmatory tests, may justify their inclusion in the makeup of Imbiza ephuzwato herbal mixture as well as their use in traditional medicine. Further studies aimed at investigating possible synergistic effects as a result of mixing plant extracts are necessary. The reported mutagenicity in Imbiza ephuzwato could be as a result of interaction of biomolecules in the heterogeneous mixture, yielding compounds that are converted to mutagenic agents by xenobiotic metabolizing enzymes. It is therefore important to carry out further studies aimed at identifying and eliminating the sources of the mutagenic compounds in the heterogeneous mixture. Copyright Â© 2010 Elsevier Ireland Ltd. All rights reserved.

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