The biochemical mechanisms of the plant activation of promutagenic aromatic amines

Wagner, Elizabeth D.; Verdier, Mary M.; Plewa, Michael J.

doi:10.1002/em.2850150411

Cited by 33 publications

(5 citation statements)

References 57 publications

(13 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It then follows that the light‐mediated conversion of C L to P L will be small compared to the uptake of P A that was formed in the aqueous medium. We also assume that metabolic (enzymatic) oxidation of PAHs, which is known to be slow in plants [36,37], will contribute negligibly to the concentration of oxidized PAHs.…”

Section: Resultsmentioning

confidence: 99%

Mechanistic quantitative structure–activity relationship model for the photoinduced toxicity of polycyclic aromatic hydrocarbons: I. Physical model based on chemical kinetics in a two‐compartment system

Krylov

Huang

Zeiler

et al. 1997

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

Abstract-A quantitative structure-activity relationship model for the photoinduced toxicity of 16 polycyclic aromatic hydrocarbons (PAHs) to duckweed (Lemna gibba) in simulated solar radiation (SSR) was developed. Lemna gibba was chosen for this study because toxicity could be considered in two compartments: water column and leaf tissue. Modeling of photoinduced toxicity was described by photochemical reactions between PAHs and a hypothetical group of endogenous biomolecules (G) required for normal growth, with damage to G by PAHs and/or photomodified PAHs in SSR resulting in impaired growth. The reaction scheme includes photomodification of PAHs, uptake of PAHs into leaves, triplet-state formation of intact PAHs, photosensitization reactions that damage G, and reactions between photomodified PAHs and G. The assumptions used were: the PAH photomodification rate is slower than uptake of chemicals into leaves, the PAH concentration in aqueous solution is nearly constant during a toxicity test, the fluence rate of actinic radiation is lower within leaves than in the aqueous phase, and the toxicity of intact PAHs in the dark is negligible. A series of differential equations describing the reaction kinetics of intact and photomodified PAHs with G was derived. The resulting equation for PAH toxicity was a function of treatment period, initial PAH concentration, relative absorbance of SSR by each PAH, quantum yield for formation of triplet-state PAH, and rate of PAH photomodification. Data for growth in the presence of intact and photomodified PAHs were used to empirically solve for a photosensitization constant (PSC) and a photomodification constant (PMC) for each of the 16 PAHs tested. For 9 PAHs the PMC dominates and for 7 PAHs the PSC dominates.

show abstract

Section: Resultsmentioning

confidence: 99%

Mechanistic quantitative structure–activity relationship model for the photoinduced toxicity of polycyclic aromatic hydrocarbons: I. Physical model based on chemical kinetics in a two‐compartment system

Krylov

Huang

Zeiler

et al. 1997

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

show abstract

“…Overall, the The question if plants convert promutagens into DNA-reactive compounds has been addressed for the first time in 1968, when Veleminsky and Gichner showed that nitrosamines were mutagenic in Arabidopsis [68]. In the following years, representatives of different chemical classes were tested in various plant systems, and positive effects were found for example with aromatic amines in tobacco [69,70]. Positive effects with promutagens were not only observed in plant bioassays but also in in vitro experiments with mammalian cell lines upon addition of plant homogenates.…”

Section: Detection Of Genotoxic Carcinogens In the Aquatic Environmentmentioning

confidence: 99%

Use of Plant Bioassays for the Detection of Genotoxins in the Aquatic Environment

Majer

Grummt²,

Uhl

et al. 2005

Acta hydrochim. hydrobiol.

View full text Add to dashboard Cite

The present article describes the use of plant bioassays for the detection of genotoxins in the aquatic environment and gives an overview of test methods, their detection spectrum for environmental mutagens and carcinogens and their limitations and pitfalls. The most widely used test systems are micronucleus assays with meiotic cells of Tradescantia and with meristematic root tip cells of Allium and Vicia. In the last years, protocols for single cell gel electrophoresis assays have been developed, which can be conducted with a variety of species. Also various gene mutation test procedures have been developed with plants but they have hardly ever been used in environmental studies. Plants detect a broad variety of environmentally relevant genotoxins, in particular directly acting compounds. Many pesticides and industrial chemicals caused positive results; plant assays are also a unique tool for the detection of DNA‐reactive carcinogenic heavy metals in the environment. In many studies with complex mixtures, positive results were obtained which indicates that plants are sufficiently sensitive to detect effects without concentration of water samples. One of the shortcomings of the use of plants as indicators is their lack of sensitivity towards certain classes of promutagens such as nitrosamines, heterocyclic amines, and polycyclic aromatic hydrocarbons (PAHs). However, the former compounds are hardly encountered in the environment and PAHs can easily be detected chemically and in other mutagenicity tests. Taken together, the currently available data show that plant bioassays are a useful component of test batteries for environmental monitoring.

show abstract

“…It then follows that the light-mediated conversion of C L to P L will be small compared to the uptake of P A that was formed in the aqueous medium. We also assume that metabolic (enzymatic) oxidation of PAHs, which is known to be slow in plants [36,37], will contribute negligibly to the concentration of oxidized PAHs.…”

Section: Simplified Scheme For Modeling Photoinduced Toxicity Of Pahsmentioning

confidence: 99%

“…Using the expression for [G] in Equation 36 and Equation 3 for the number of leaves, N, as a function of [G], N ϭ k[G], one obtains…”

Section: Relationship Of the Number Of Leaves To [G]mentioning

confidence: 99%

Mechanistic Quantitative Structure–activity Relationship Model for the Photoinduced Toxicity of Polycyclic Aromatic Hydrocarbons: I. Physical Model Based on Chemical Kinetics in a Two-Compartment System

Krylov¹,

Huang²,

Zeiler³

et al. 1997

Environ Toxicol Chem

123

View full text Add to dashboard Cite

A quantitative structure-activity relationship model for the photoinduced toxicity of 16 polycyclic aromatic hydrocarbons (PAHs) to duckweed (Lemna gibba) in simulated solar radiation (SSR) was developed. Lemna gibba was chosen for this study because toxicity could be considered in two compartments: water column and leaf tissue. Modeling of photoinduced toxicity was described by photochemical reactions between PAHs and a hypothetical group of endogenous biomolecules (G) required for normal growth, with damage to G by PAHs and/or photomodified PAHs in SSR resulting in impaired growth. The reaction scheme includes photomodification of PAHs, uptake of PAHs into leaves, triplet-state formation of intact PAHs, photosensitization reactions that damage G, and reactions between photomodified PAHs and G. The assumptions used were: the PAH photomodification rate is slower than uptake of chemicals into leaves, the PAH concentration in aqueous solution is nearly constant during a toxicity test, the fluence rate of actinic radiation is lower within leaves than in the aqueous phase, and the toxicity of intact PAHs in the dark is negligible. A series of differential equations describing the reaction kinetics of intact and photomodified PAHs with G was derived. The resulting equation for PAH toxicity was a function of treatment period, initial PAH concentration, relative absorbance of SSR by each PAH, quantum yield for formation of triplet-state PAH, and rate of PAH photomodification. Data for growth in the presence of intact and photomodified PAHs were used to empirically solve for a photosensitization constant (PSC) and a photomodification constant (PMC) for each of the 16 PAHs tested. For 9 PAHs the PMC dominates and for 7 PAHs the PSC dominates.

show abstract

The biochemical mechanisms of the plant activation of promutagenic aromatic amines

Cited by 33 publications

References 57 publications

Mechanistic quantitative structure–activity relationship model for the photoinduced toxicity of polycyclic aromatic hydrocarbons: I. Physical model based on chemical kinetics in a two‐compartment system

Mechanistic quantitative structure–activity relationship model for the photoinduced toxicity of polycyclic aromatic hydrocarbons: I. Physical model based on chemical kinetics in a two‐compartment system

Use of Plant Bioassays for the Detection of Genotoxins in the Aquatic Environment

Mechanistic Quantitative Structure–activity Relationship Model for the Photoinduced Toxicity of Polycyclic Aromatic Hydrocarbons: I. Physical Model Based on Chemical Kinetics in a Two-Compartment System

Contact Info

Product

Resources

About