Review of mutagenicity of monocyclic aromatic amines: quantitative structure–activity relationships

Chung, King‐Thom; Kirkovsky, Leonid; Kirkovsky, Alexander; Purcell, William P.

doi:10.1016/s1383-5742(97)00019-7

Cited by 87 publications

(55 citation statements)

References 61 publications

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“…2,4-DAT has been shown to be carcinogenic to mammals, and is considered a direct mutagen (National Cancer Institute, 1978;Chung et al, 1997). Though the compound may have adverse health effects, the fate of 2,4-DAT is on the order of days in natural environments.…”

Section: A-4 Discussionmentioning

confidence: 99%

Arsenic Removal Using Iron-Modified Zeolites

Andrews¹

2016

Geological Society of America Abstracts With Programs

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We determined the ability of two iron-and-zeolite materials to remove arsenic from groundwater. The first material is composed of iron, surfactant-modified zeolite, and hard silicate foam, and is known as Surfactant-Modified Zeolite/ Zero-Valent Iron (SMZ/ZVI). The second material is a new formulation that consists of iron-modified zeolite (IMZ). We prepared eight different prototypes of IMZ for arsenic removal and eventually used one for further testing. The iron content, surface area, and arsenic adsorption capacity were analyzed for each fully prepared material.Lab-based batch experiments were performed on each material to estimate the adsorption capacity. Additionally, the effect of pH on adsorption and the rate of adsorption were determined for the SMZ/ZVI material and one of the newly prepared IMZ. All batch tests were performed using synthetic water based on the chemistry of Socorro Springs water from Socorro, NM. Batch isotherms were performed on each IMZ material using arsenic concentrations that ranged from 10 -200 mg/L. Batch experiments were accompanied by small-scale column experiments in the lab, and in the case of SMZ/ZVI, a field column test was performed at a wellhead. All of the water used in the column experiments was sourced from the Socorro Springs near the city of Socorro, NM (containing 41-45 µg/L arsenate, pH = 8.1, and TDS = 356 µS/cm), and was transported to the lab for column testing. Influent and effluent arsenic concentrations, column flowrates, and total volume were measured in each column study. The measured parameters were used to calculate the volume of water treated below EPA arsenic concentration specifications. All arsenic concentrations were obtained using a hydride generation method coupled with Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES).The batch experiments showed that the SMZ/ZVI has a maximum arsenic adsorption capacity as calculated by the Langmuir isotherm of 512 mg/kg. The pH study showed that maximum arsenic adsorption occurs at pH 6.5 and that sorption decreases below or above this pH value. The kinetic studies showed that 95% adsorption is achieved in less than 2 minutes at low concentrations (66 µg/L) and The arsenic adsorption capacity varied greatly between the different types of newly created IMZ and was heavily dependent on the procedures used for iron application. The most successful technique that resulted in good iron coating coverage, robustness, and a high arsenic adsorption capacity was a multi-step process that coated the iron on the zeolite in several smaller amounts rather than one large loading. The material chosen is labeled IMZ-8 and contained 28,400 mg of iron per kg material.Compared with the raw zeolite that had a surface are of 13.8 m²/g, the surface area of IMZ-8 increased about 150% to 21.4 m²/g. Using the Langmuir isotherm, IMZ-8 had a maximum arsenic adsorption capacity of 654 mg/ kg and a Langmuir coefficient of 4.65 L/mg. The IMZ-8 material was further tested by looking at the effects of pH on adsorption an...

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Section: A-4 Discussionmentioning

confidence: 99%

Arsenic Removal Using Iron-Modified Zeolites

Andrews¹

2016

Geological Society of America Abstracts With Programs

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“…For instance, 4-amino-3-nitro-2,5-dimethylaniline is a GT+ agent, while its analogue 4-amino-3-nitro-2,6-dimethylaniline is GT- (58). Four molecular connectivity descriptors, 3 C , 4 PC , 3 C v , and 4 PC v , are selected by RFE in this work.…”

Section: Relevance Of Selected Features To Genotoxicty Studymentioning

confidence: 99%

Prediction of Genotoxicity of Chemical Compounds by Statistical Learning Methods

Ung

Yap

et al. 2005

Chem. Res. Toxicol.

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Various toxicological profiles, such as genotoxic potential, need to be studied in drug discovery processes and submitted to the drug regulatory authorities for drug safety evaluation. As part of the effort for developing low cost and efficient adverse drug reaction testing tools, several statistical learning methods have been used for developing genotoxicity prediction systems with an accuracy of up to 73.8% for genotoxic (GT+) and 92.8% for nongenotoxic (GT-) agents. These systems have been developed and tested by using less than 400 known GT+ and GTagents, which is significantly less in number and diversity than the 860 GT+ and GT-agents known at present. There is a need to examine if a similar level of accuracy can be achieved for the more diverse set of molecules and to evaluate other statistical learning methods not yet applied to genotoxicity prediction. This work is intended for testing several statistical learning methods by using 860 GT+ and GT-agents, which include support vector machines (SVM), probabilistic neural network (PNN), k-nearest neighbor (k-NN), and C4.5 decision tree (DT). A feature selection method, recursive feature elimination, is used for selecting molecular descriptors relevant to genotoxicity study. The overall accuracies of SVM, k-NN, and PNN are comparable to and those of DT lower than the results from earlier studies, with SVM giving the highest accuracies of 77.8% for GT+ and 92.7% for GT-agents. Our study suggests that statistical learning methods, particularly SVM, k-NN, and PNN, are useful for facilitating the prediction of genotoxic potential of a diverse set of molecules.

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“…They are also formed in the environment during the microbial transformation of nitroaromatic compounds and aniline-based pesticides (Kearney & Kaufman, 1975). Since many of them are known to be toxic, mutagenic and carcinogenic (Crabtree et al, 1991;Chung et al, 1997;Bhunia et al, 2003), their fate in the environment and biodegradation have been extensively studied (Bollag et al, 1978;Lyons et al, 1984Lyons et al, , 1985.…”

Section: Introductionmentioning

confidence: 99%

Chromosome-encoded gene cluster for the metabolic pathway that converts aniline to TCA-cycle intermediates in Delftia tsuruhatensis AD9

et al. 2005

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Delftia tsuruhatensis AD9 was isolated as an aniline-degrading bacterium from the soil surrounding a textile dyeing plant. The gene cluster involved in aniline degradation was cloned from the total DNA of strain AD9 into Escherichia coli JM109. After shotgun cloning, two recombinant E. coli strains showing aniline oxidation activity or catechol meta-cleavage activity were obtained by simple plate assays. These strains contained 9?3 kb and 15?4 kb DNA fragments, respectively. Sequence analysis of the total 24?7 kb region revealed that this region contains a gene cluster (consisting of at least 17 genes, named tadQTA1A2BRD1C1D2C2EFGIJKL) responsible for the complete metabolism of aniline to TCA-cycle intermediates. In the gene cluster, the first five genes (tadQTA1A2B) and the subsequent gene (tadR) were predicted to encode a multi-component aniline dioxygenase and a LysR-type regulator, respectively, while the others (tadD1C1D2C2EFGIJKL) were expected to encode meta-cleavage pathway enzymes for catechol degradation. In addition, it was found that the gene cluster is surrounded by two IS1071 sequences, indicating that it has a class I transposon-like structure. PFGE and Southern hybridization analyses confirmed that the tad gene cluster is encoded on the chromosome of strain AD9 in a single copy. These results suggest that, in strain AD9, aniline is degraded via catechol through a meta-cleavage pathway by the chromosome-encoded tad gene cluster. The tad gene cluster showed significant similarity in nucleotide sequence and genetic organization to the plasmid-encoded aniline degradation gene cluster of Pseudomonas putida UCC22.

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Review of mutagenicity of monocyclic aromatic amines: quantitative structure–activity relationships

Cited by 87 publications

References 61 publications

Arsenic Removal Using Iron-Modified Zeolites

Arsenic Removal Using Iron-Modified Zeolites

Prediction of Genotoxicity of Chemical Compounds by Statistical Learning Methods

Chromosome-encoded gene cluster for the metabolic pathway that converts aniline to TCA-cycle intermediates in Delftia tsuruhatensis AD9

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