Chemical reactions producing chrysene as an artifact of some K-region metabolites of benzo(a)pyrene.
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Animals↗
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Quantitative microspectrofluorimetry study of the "blocking effect" of 6-aminochrysene on benzo[a]pyrene metabolism using single living cells.
By microspectrofluorimetry on single living cells (murine fibroblasts 3T3), we have obtained monoexponential decreases of fluorescence intensity for benzo[a]pyrene (B[a]P) and 6-aminochrysene (6a-chrysene) metabolism. These kinetics are characteristics of B[a]P and 6a-chrysene metabolism and histograms can be drawn from the rate constants. We have studied the influence of 6a-chrysene on B[alpha]P metabolism. Using different methods of incubation, it has been observed that the presence of 6a-chrysene leads to modifications of the histogram profiles during B[a]P metabolism. Polycyclic aromatic hydrocarbons (PAH) are used to induce B[a]P metabolism. Whatever the experimental conditions we never detected such a phenomenon with 6a-chrysene. On the contrary we have observed an inhibition of B[a]P metabolism by 6a-chrysene, which can reach 80% of the aryl hydrocarbon hydroxylase (AHH) activity when 6a-chrysene remains constant in the cells. Compared with the results previously observed "in vitro" which presented 50% mean inhibition) we show that inhibition acts in an all-or-nothing mechanism at the cellular level.
Animals↗
Fjord- and bay-region diol-epoxides investigated for stability, SOS induction in Escherichia coli, and mutagenicity in Salmonella typhimurium and mammalian cells.
The fjord-region diol-epoxides of benzo(c)phenanthrene combine high mutagenic and carcinogenic activity with low chemical reactivity. To study whether this is a unique property of these compounds or a more general characteristic of fjord-region diol-epoxides, we have synthesized the anti- and syn-diastereomers of r-9,t-10-dihydroxy-11,12-oxy-9,10,11,12-tetrahydrobenzo(c)chrysene and r-11-t-12-dihydroxy-13,14-oxy-11,12,13,14-tetrahydrobenzo(g)chrysene. These compounds as well as the anti- and syn-diastereomers of the fjord-region diol-epoxides of benzo(c)phenanthrene and of the bay-region diol-epoxides of phenanthrene, chrysene, and benzo(a)pyrene were investigated for their half-lives in a physiological buffer, for their mutagenicity in Salmonella typhimurium (reversion of the his- strains TA97, TA98, TA100, and TA104), for induction of SOS response in Escherichia coli (SOS chromotest in strain PQ37) and for their mutagenicity in V79 Chinese hamster cells (acquisition of resistance to 6-thioguanine). All six of the investigated fjord-region diol-epoxides were more stable in physiological buffer at 37 degrees C (t1/2 greater than 2 h) than the six bay-region diol-epoxides (t1/2 = 0.011 to 1.2 h). The half-lives correlated negatively with the calculated delta Edeloc values for the formation of the benzylic carbocations, and were consistently shorter for the syn- than for the corresponding anti-diastereomer. All fjord-region diol-epoxides showed extraordinarily high activity in all six genotoxicity assays used. In mammalian cells, the anti-diol-epoxide of benzo(c)chrysene was 8.6 and 12 times more active than the anti-diol-epoxides of benzo(c)phenanthrene and benzo(a)pyrene, respectively, which were the most potent mutagens among the reference compounds. The other three newly available fjord-region diol-epoxides were also markedly more mutagenic in mammalian cells than the reference compounds. Whereas the syn-diastereomers of the simple bay-region diolepoxides were clearly less mutagenic in mammalian cells than the corresponding anti-diastereomers, the differences in potency between diastereomers were small for the fjord-region diol-epoxides. In conclusion, the diol-epoxides of benzo(c)phenanthrene are not unique in their high biological activities. The two newly available diastereomeric pairs of fjord-region diol-epoxides of benzo(g)- and benzo(c)chrysene proved to be even more active. For one of them, the diol-epoxides of benzo(g)chrysene, the delta Edeloc value for the formation of the benzylic carbocation is lower than for the benzo(c)phenanthrene diol-epoxides, for the other it is higher.
7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
Semiquantitative confocal laser scanning microscopy applied to marine invertebrate ecotoxicology.
Confocal laser scanning microscopy (CLSM) represents a powerful, but largely unexplored ecotoxicologic tool for rapidly assessing in vivo effects of toxicants on marine invertebrate embryo quality and development. We describe here a new semiquantitative CLSM approach for assessing relative yolk quantity in marine invertebrate embryos (harpacticoid copepods) produced by parents reared from hatching to adult in the polycylic aromatic hydrocarbon chrysene. This method is based on fluorogenic labeling of embryo yolk and subsequent statistical analysis of areal pixel intensities over multiple Z-series using a general linear model (GLM)-nested analysis of variance. The fluorescent yolk-labeling method described here was able to detect statistically significant differences in yolk concentrations in marine copepod (Amphiascus tenuiremis) eggs or embryos from females exposed to ultraviolet light and chrysene-contaminated sediments. Yolk intensities in embryos from females cultured throughout their life cycles in clean sediments were statistically identical with or without UV exposure. In contrast, yolk intensities in embryos of females cultured throughout their life cycle in chrysene-contaminated sediments were significantly higher in the non-UV-exposed treatment with chrysene at 2500 ng/g sediment (65.7% higher) and the UV-exposed treatment with chrysene at 500 ng/g sediment (76.6% higher).
Animals↗
Identification and functional analysis of two aromatic-ring-hydroxylating dioxygenases from a sphingomonas strain that degrades various polycyclic aromatic hydrocarbons.
In this study, the enzymes involved in polycyclic aromatic hydrocarbon (PAH) degradation in the chrysene-degrading organism Sphingomonas sp. strain CHY-1 were investigated. [14C]chrysene mineralization experiments showed that PAH-grown bacteria produced high levels of chrysene-catabolic activity. One PAH-induced protein displayed similarity with a ring-hydroxylating dioxygenase beta subunit, and a second PAH-induced protein displayed similarity with an extradiol dioxygenase. The genes encoding these proteins were cloned, and sequence analysis revealed two distinct loci containing clustered catabolic genes with strong similarities to corresponding genes found in Novosphingobium aromaticivorans F199. In the first locus, two genes potentially encoding a terminal dioxygenase component, designated PhnI, were followed by a gene coding for an aryl alcohol dehydrogenase (phnB). The second locus contained five genes encoding an extradiol dioxygenase (phnC), a ferredoxin (phnA3), another oxygenase component (PhnII), and an isomerase (phnD). PhnI was found to be capable of converting several PAHs, including chrysene, to the corresponding dihydrodiols. The activity of PhnI was greatly enhanced upon coexpression of genes encoding a ferredoxin (phnA3) and a reductase (phnA4). Disruption of the phnA1a gene encoding the PhnI alpha subunit resulted in a mutant strain that had lost the ability to grow on PAHs. The recombinant PhnII enzyme overproduced in Escherichia coli functioned as a salicylate 1-hydroxylase. PhnII also used methylsalicylates and anthranilate as substrates. Our results indicated that a single enzyme (PhnI) was responsible for the initial attack of a range of PAHs, including chrysene, in strain CHY-1. Furthermore, the conversion of salicylate to catechol was catalyzed by a three-component oxygenase unrelated to known salicylate hydroxylases.
Amino Acid Sequence↗
Two-liquid-phase slurry bioreactors to enhance the degradation of high-molecular-weight polycyclic aromatic hydrocarbons in soil.
High-molecular-weight (HMW) polycyclic aromatic hydrocarbons (PAHs) are pollutants that persist in the environment due to their low solubility in water and their sequestration by soil and sediments. The addition of a water-immiscible, nonbiodegradable, and biocompatible liquid, silicone oil, to a soil slurry was studied to promote the desorption of PAHs from soil and to increase their bioavailability. First, the transfer into silicone oil of phenanthrene, pyrene, chrysene, and benzo[a]pyrene added to a sterilized soil (sandy soil with 0.65% total volatile solids) was measured for 4 days in three two-liquid-phase (TLP) slurry systems each containing 30% (w/v) soil but different volumes of silicone oil (2.5%, 7.5%, and 15% [v/v]). Except for chrysene, a high percentage of these PAHs was transferred from soil to silicone oil in the TLP slurry system containing 15% silicone oil. Rapid PAH transfer occurred during the first 8 h, probably resulting from the extraction of nonsolubilized and of poorly sorbed PAHs. This was followed by a period in which a slower but constant transfer occurred, suggesting extraction of more tightly bound PAHs. Second, a HMW PAH-degrading consortium was enriched in a TLP slurry system with a microbial population isolated from a creosote-contaminated soil. This consortium was then added to three other TLP slurry systems each containing 30% (w/v) sterilized soil that had been artificially contaminated with pyrene, chrysene, and benzo[a]pyrene, but different volumes of silicone oil (10%, 20%, and 30% [v/v]). The resulting TLP slurry bioreactors were much more efficient than the control slurry bioreactor containing the same contaminated soil but no oil phase. In the TLP slurry bioreactor containing 30% silicone oil, the rate of pyrene degradation was 19 mg L(-)(1) day(-)(1) and no pyrene was detected after 4 days. The degradation rates of chrysene and benzo[a]pyrene in the 30% TLP slurry bioreactor were, respectively, 3.5 and 0.94 mg L(-)(1) day(-)(1). Low degradation of pyrene and no significant degradation of chrysene and benzo[a]pyrene occurred in the slurry bioreactor. This is the first report in which a TLP system was combined with a slurry system to improve the biodegradation of PAHs in soil.
Biodegradation, Environmental↗
Self-assembly of small polycyclic aromatic hydrocarbons on graphite: a combined scanning tunneling microscopy and theoretical approach.
Self-assembled monolayers of chrysene and indene on graphite have been observed and characterized individually with scanning tunneling microscopy (STM) at 80 K under low-temperature, ultrahigh vacuum conditions. These molecules are small, polycyclic aromatic hydrocarbons (PAHs) containing no alkyl chains or functional groups that are known to promote two-dimensional self-assembly. Energy minimization and molecular dynamics simulations performed for small groups of the molecules physisorbed on graphite provide insight into the monolayer structure and forces that drive the self-assembly. The adsorption energy for a single chrysene molecule on a model graphite substrate is calculated to be 32 kcal/mol, while that for indene is 17 kcal/mol. Two distinct monolayer structures have been observed for chrysene, corresponding to high- and low-density assemblies. High-resolution STM images taken of chrysene with different bias polarities reveal distinct nodal structure that is characteristic of the molecular electronic state(s) mediating the tunneling process. Density functional theory calculations are utilized in the assignment of the observed electronic states and possible tunneling mechanism. These results are discussed within the context of PAH and soot particle formation, because both chrysene and indene are known reaction products from the combustion of small hydrocarbons. They are also of fundamental interest in the fields of nanotechnology and molecular electronics.
Journal Article↗
Class-specific immunoadsorption purification for polycyclic aromatic hydrocarbon-DNA adducts.
An immunoenrichment procedure has been developed for applications in the detection and identification of a broad range of polycyclic aromatic hydrocarbon (PAH)-DNA adducts at very low abundance. The procedures are based on a monoclonal antibody raised to r-7,trans-8,trans-9-trihydroxy-cis-10-(N2-deoxyguanosyl-5'-phospha te)- 7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE-N2-dG) which has been tested for cross-reactivity towards DNA and proteins (bovine serum albumin, chicken gamma globulin and human globin) covalently modified with a range of PAH diol-epoxides. The antibody recognised DNA adducted with the diol-epoxides of benzo[a]pyrene, benz[a]anthracene, chrysene, dibenz[a,h]anthracene or picene. The antibody also cross-reacted with the 7,8,9,10-tetraol derived from benzo[a]pyrene and the 1,2,3,4-tetraols of benz[a]anthracene and chrysene. The degree of cross-reactivity was greatest for PAH adducts with structural features similar to anti-BPDE-N2-dG proximate to the base attachment. The antibody also recognised a range of PAHs adducted to human globin; these included adducts of benzo[a]pyrene, benz[a]anthracene and chrysene diol-epoxides. This wide range of recognition provides good evidence for the class-specific recognition of PAH adducts by the antibody. When immobilized on Sepharose 4B and used in the immunoadsorption purification of adducted nucleotides, the antibody selectively enriched adducts of benzo[a]pyrene, benz[a]anthracene and chrysene from normal nucleotides. Quantitative measurements with [14C]benzo[a]pyrene-DNA adducts showed that the immobilized antibody was able to enrich benzo[a]pyrene adducts from a DNA hydrolysate containing adducts at a level of 1 adduct/10(10) normal nucleotides. In addition, this immunoadsorption technique was effective in enriching a mixture of DNA adducts formed in the skin of CF1 mice treated cutaneously with a mixture of [3H]benzo[a]pyrene and [3H]chrysene. Class-specific immunoenrichment procedures for DNA adducts are important in assisting the identification of genotoxic components in complex mixtures. The performance characteristics of this immobilized antibody suggest that it may be suitable for application in the detection, identification and monitoring of human exposures to low levels of PAHs.
Animals↗
Particle-mediated membrane uptake of chemical carcinogens studied by fluorescence spectroscopy.
The fluorescence emissions of chrysene, N-ethylcarbazole, and 1,6-diphenylhexatriene undergo large spectral shifts or changes in quantum yield, or both, upon their uptake from particulates by phospholipid vesicles. This membrane uptake of carcinogen and carcinogen-like molecules by model membranes does not result in any disruption of the lipid bilayers. The fluorescence emission of chrysene, when bound to silica, was found to be sensitive to the surface density of chrysene on the silica. These observations demonstrate the feasibility of using fluorescence spectroscopy to measure the rates of exchange of carcinogens from particulate matter to cell membranes and to characterize the surface distribution of chemical carcinogens on particulate matter. Comparison of the uptake rate of chrysene from the unperturbed crystal state, sonicated crystals, and the silica-adsorbed state demonstrated that the last condition results in the most rapid transport of chrysene into model membranes. This information should prove valuable in understanding the cocarcinogenic effects of particulates and polynuclear aromatic hydrocarbons.
Carcinogens↗
Selective activation of some dihydrodiols of several polycyclic aromatic hydrocarbons to mutagenic products by prostaglandin synthetase.
The ability of prostaglandin synthetase (PGS) to cooxidize benzo(a)pyrene, benzo(a)anthracene, chrysene, and several of their dihydrodiol derivatives to mutagenic products was tested with Salmonella typhimurium strains TA98 and TA100. The microsomal fraction of ram seminal vesicles, a known source of PGS, in the presence of the PGS substrate arachidonic acid, metabolized benzo(a)pyrene-7,8-dihydrodiol, benzo(a)anthracene-3,4-dihydrodiol, and chrysene-1,2-dihydrodiol to mutagenic products. This activity was inhibited by the PGS inhibitor indomethacin. Unlike the PGS system, however, a cytochrome P-450-reduced nicotinamide adenine dinucleotide phosphate-dependent system, present in an Aroclor 1254-induced rat liver 9000 x g supernatant fraction, also activated the parent compounds [benzo(a)pyrene, benzo(a)anthracene, chrysene] and several other benzo(a)anthracene dihydrodiols (the 1,2-dihydrodiol, the 8,9-dihydrodiol, and the 10,11-dihydrodiol). The chrysene trans-3,4, trans-5,6, and cis-5,6 diols were not activated to mutagens by either system. Thus, the PGS system appears to be more selective than does the cytochrome P-450 system in the activation of polycyclic aromatic hydrocarbons to mutagenic products, activating only those dihydrodiols with adjacent double bonds in the bay region from which the bay-region diol-epoxides are formed.
Animals↗
Comparison of properties on non-protected fluid room temperature phosphorescence of some tetra-ring aromatic hydrocarbons.
A comparative study of the photoluminescence properties of three kinds of tetra-ring aromatic hydrocarbon (1-sodium pyrenesulphonate, benz[alpha]anthracene and chrysene) solution in the absence of any protecting medium is described. It was found that a room temperature phosphorescence signal with different intensities can be induced for these solutions, using only TlNO3 or KI as a heavy atom perturber (HAP) and Na2SO3 as a deoxygenator. An appropriate amount of organic solvent added to the systems of pyrene, benz[alpha]anthracene and chrysene is necessary for increasing the solubility and phosphorescence intensity, and the preferable solvent is acetonitrile. For the pyrene, pyrenesulphonate and chrysene systems, a delayed excimer fluorescence accompanied with the room temperature phosphorescence (RTP) emission can be observed, but that for benz[alpha]anthracene cannot. The ratio of delayed excimer fluorescence and phosphorescence signals for pyrene, pyrenesulphonate and chrysene systems can be controlled by adjusting the concentration of luminophor, kinds and amount of both organic solvents and HAP. Under the optimal conditions, the RTP signals are proportional to the concentration of the four aromatic hydrocarbons, which means that the RTP properties of the four tetra-ring aromatic hydrocarbons can be used for quantitative analysis.
Cyclization↗
Immunosuppressive potential of several polycyclic aromatic hydrocarbons (PAHs) found at a Superfund site: new model used to evaluate additive interactions between benzo[a]pyrene and TCDD.
Exposure to environmental pollution is rarely limited to a single compound or even a single class of compounds. The Superfund site located in Massena, NY, is contaminated by both halogenated aromatic hydrocarbons (HAHs) and polycyclic aromatic hydrocarbons (PAHs). Since representatives of both HAHs and PAHs are capable of binding to the aromatic hydrocarbon receptor (AhR), two well-documented AhR-mediated effects, immunosuppression and induction of hepatic aryl hydrocarbon hydroxylase (AHH) activity, were used to evaluate the individual and interactive toxicity of these compounds. Fifteen PAHs were first screened for their ability to suppress the antibody response in C57BL/6 (Ah+/+) mice immunized 12 h after a single oral dose of 0.1, 1, 10, or 100 mg/kg. Acenaphthene, anthracene, benzo[g,h,i]perylene, fluoranthene, fluorene, naphthalene, phenanthrene, and pyrene had little or no effect. Seven PAHs caused > 50% suppression at 100 mg/kg. Listed in order of decreasing potency they were benzo[k]fluoranthene, benzo[b]fluoranthene, indeno[1,2,3,c,d]pyrene, benzo[a]pyrene, chrysene, dibenzo[a,h]anthracene, and benz[a]anthracene. Chrysene and benzo[a]pyrene (B[a]P), were further evaluated to determine the dependence of these effects on the Ah phenotype by comparing responses of C57BL/6 and congenic B6.D2 (Ah-/-) mouse strains. Chrysene immunosuppression was maximal at 0.1 mg/kg and was Ah phenotype-independent whereas chrysene AHH induction was Ah phenotype-dependent, but a 100-fold less sensitive indicator of exposure. In contrast, B[a]P immunosuppression and AHH induction were coincident in B6 mice and Ah phenotype-dependent. In the final phase, a new approach was used to evaluate toxic interactions. This approach considers the mechanism of action of each compound and accounts for the fact that the extent of increase in toxic response caused by an incremental change of dose is determined by its position on the dose-response curve rather than on the absolute amount of dose administered. Thus, the immunotoxic effects of combined exposure to B[a]P and the AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a representative HAH, were evaluated by combining the ED20 of B[a]P with the difference between the ED20 and ED40 of TCDD, and vice versa, to produce 40% suppression. The results of the combination were consistent with additivity regardless of the composite arrangement or phenotype although some antagonism could not be excluded with certainty.
Animals↗
32P-postlabeling and HPLC separation of DNA adducts formed by diesel exhaust extracts in vitro and in mouse skin and lung after topical treatment.
Diesel exhaust extracts contain many carcinogenic compounds which have been shown to form polycyclic aromatic hydrocarbon (PAH)- and nitrated PAH-DNA adducts in rodent skin and lung. The aim of this study was to characterize by 32P-postlabeling, TLC and HPLC the primary postlabeled PAH-DNA adduct(s) formed in vitro and in vivo by diesel extracts. The diesel particle extracts had known concentrations of benzo[a]pyrene, benzo[b,j,k]-fluoranthenes (B[b,j,k]F) and chrysene. DNA adducts were analyzed in calf thymus DNA incubated in vitro with PAHs activated by S9 mix and in skin and lung DNA from topically treated mice. The main diesel-derived DNA adduct formed in vitro and in vivo did not co-migrate on HPLC and large TLC plates with (+/-)-r-7,t-8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti BPDE)-, B[b]F-,B[j]F-,B[k]F-or chrysene-DNA adduct standards. By co-chromatography DNA adducts formed by chrysene from both in vitro and in vivo samples were identified. Nissan diesel extract containing higher PAH concentrations than Volkswagen automobile extract formed skin DNA adducts that co-migrated with chrysene- and anti BPDE- DNA-derived adducts. We conclude that the use of a highly sensitive 32P-postlabeling method combined with HPLC improves the identification of PAH adducts formed by complex mixtures such as diesel exhaust extracts.
7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
Uptake and diverse effects of polycyclic aromatic hydrocarbons on the metabolic activity of Elliptio complanata measured by calorespirometry.
Polycyclic aromatic hydrocarbons (PAHs) are important contaminants of world water resources, with effects on aquatic life. Metabolic responses to short-term acute toxicities of naphthalene, anthracene, and chrysene were investigated in the freshwater bivalve mollusk Elliptio complanata using differential scanning calorespirometry coupled with uptake and scanning electron microscopy. Comparing the uptakes of naphthalene, anthracene, and chrysene with that of inulin, which is known to occupy only extracellular space, showed that all compounds studied were taken up. The PAHs studied had diverse effects on the metabolic activity of E. complanata. Naphthalene and, to a lesser degree, chrysene caused stimulation of heat rates, possibly due to uncoupling of oxidative metabolism. Differential scanning calorespirometry coupled with studies of rates of oxygen consumption by the gill tissue exposed to the PAHs showed similar diverse patterns of respiratory rate stimulation and inhibition. Analysis of results of scanning electron microscopy suggested that irreversible damage to the gill tissue occurred in the presence of anthracene but not in the presence on naphthalene or chrysene. The batch calorespirometric method coupled with uptake and spectroscopy proved to be a useful technique to assess the toxicity of PAHs on the control of energy flux in gills of a freshwater bivalve mollusk.
Animals↗
Substituent effects and charge delocalization mode in chrysenium, benzo[c]phenanthrenium, and benzo[g]chrysenium cations: a stable ion and electrophilic substitution study.
The first series of persistent carbocations derived from mono- and disubstituted chrysenes Ch (5- methyl- 3, 2-methoxy- 19, 2-methoxy-11-methyl- 20, 2-methoxy-5-methyl- 21, and 9-methyl-4H-cyclopenta[def]chrysene 22), monosubstituted benzo[c]phenanthrenes BcPh (3-methoxy- 23, 3-hydroxy- 24), and monosubstituted benzo[g]chrysenes BgCh (12-methoxy- 25; 12-hydroxy- 26) were generated in FSO3H/SO2ClF or FSO3H-SbF5 (4:1)/SO2ClF and studied by low-temperature NMR at 500 MHz. The methoxy and methyl substituents direct the protonation to their respective ortho positions. Whereas parent Ch 1 is protonated at C-6/C-12, 3 is protonated at C-6 (3aH+) and at C-12 (3bH+) with the latter being the thermodynamic cation. The 2-methoxy-Ch 19 is protonated at C-1 to give two conformationally distinct carboxonium ions (19aH+/19bH+). In the disubstituted Ch derivatives 20 and 21, the 2-methoxy overrides the 5-methyl and the predominant carbocations formed are via attack ortho to methoxy. For the methano derivative 22 (Me at C-9), a 3:1 mixture of 22aH+/22bH+ is formed. For parent BcPh 13, nitration and benzoylation are directed to C-5. With 3-methoxy-BcPh 23, the site of attack moves to C-4, thus producing two conformationally distinct carboxonium ions (23aH+/23bH+), whereas conventional nitration gave a 2:1 mixture of 23aNO2 and 23bNO2. In 3-hydroxy-BcPh 24, the carboxonium ion 24H+ is exclusively formed. For parent BgCh 16, protonation, nitration, and benzoylation are all directed to C-10 (16H+, 16NO2, 16COPh), but presence of OMe or OH substituent at C-12 changes the site of attack to C-11. Charge delocalization mode is probed based on magnitude of delta delta 13Cs and conformational aspects via NOED experiments. Complete NMR data are also reported for several benzoylation/nitration products. Using ab initio/GIAO (and NICS), the NMR chemical shifts (and aromaticity) in model carbocations A-D were evaluated. This work represents the first direct study of the carbocations derived from the methyl-, methoxy-/hydroxy-derivatives of three important classes of bay-region and fjord-region PAHs whose diol-epoxides extensively bind to DNA. It also extends the available data on electrophilic chemistry of BcPh and BgCh.
Chrysenes↗
Detection and characterization of human serum antibodies to polycyclic aromatic hydrocarbon diol-epoxide DNA adducts.
The presence of serum antibodies to the diol-epoxide DNA adducts of representative polycyclic aromatic hydrocarbons (PAH), chrysene, benz[a]anthracene and benzo[a]pyrene, was determined by ELISA using serum samples obtained from normal healthy individuals. Antibodies that reacted against PAH adducted-DNA, but not against PAH-adducted protein, were found in the serum of approximately 40% of the test individuals. Specificity analysis of the antibodies demonstrated that serological cross-reactions between the benzo[a]pyrene and the chrysene diol-epoxide adducts were present. Similar cross-reactivity between the benz[a]anthracene and the chrysene adducts was observed. Sera containing antibodies that were apparently specific for each of the three PAH-DNA adducts were also identified. The presence of antibodies to PAH-DNA adducts indicates both past exposure to these carcinogenic PAH and their metabolic activation to the DNA damaging metabolites. These antibodies may prove to be useful in both retrospective and prospective epidemiological studies of various diseases associated with PAH exposure.
Adult↗
[An animal experimental study on the retention rate of polycyclic aromatic hydrocarbons in the lung and in the subcutaneous tissue (author's transl)].
The retention rate of five polyaromatic hydrocarbons (PAH) (benzo(a)pyrene, dibenz(ah)anthracene, chrysene, pyrene, benz(a) anthracene) was studied after intratracheal instillation into syrian hamsters and subcutanous injection into mice. For subcutanous injection the PAH were solved in 0.5 ml tricaprylin, for intratracheal instillation a suspension in NaCl was used. The results were the following: 1. With respect to the retention rate of the five PAH the largest difference was found comparing the application modes. The ratio of the averaged half-time-values for the intratracheal test to the subcutanous test is about 1:35. 2. The retention rates for each polycyclic hydrocarbon differs significantly. An interrelation of PAH after application of a PAH-mixture was not detectable. 3. The retention rates determined in the lung and in the subcutanous tissue do not give a constant ratio concerning each PAH. Thus DBahA is retained in the lung as well as in the subcutanous tissue definitely longer than BaP. Chrysene and benz(a)anthracene behave - respecting the retention rate - in the subcutanous test like BaP. In lung tissue, however, the different behaviour becomes obvious: while benz(a)anthracene is eliminated most rapidly, chrysene can be detected for a relative long time.
Animals↗
The anti-estrogenic activity of selected polynuclear aromatic hydrocarbons in yeast expressing human estrogen receptor.
Polynuclear aromatic hydrocarbons (PAH) represent a large class of chemicals present in environment. We have used yeast strain ER(wt) expressing human estrogen receptor (hER) and an estrogen-sensitive reporter to characterize the estrogenic or anti-estrogenic activities of 21 PAHs. The PAHs did not exhibit estrogenic activity in yeast strain ER(wt). Four of the PAHs, dibenz[a,h]anthracene, 6-hydroxy-chrysene, 2,3-benzofluorene, and benzo(a)pyrene, inhibited estradiol-dependent reporter activity in strain ER(wt). A mutant hER lacking the amino terminus expressed in yeast was inhibited by the four PAHs to a lesser extent than the full-length hER. 6-hydroxy-chrysene, 2,3-benzofluorene, and benzo(a)pyrene, but not dibenz[a,h]anthracene, weakly displaced [3H]estradiol from the hER in a competition binding assay. A strong correlation between the inhibition of [3H]estradiol-binding from the hER and the reduction of hER-mediated transactivation in yeast was not observed. These observations suggest that the PAHs dibenz[a,h]-anthracene, 6-hydroxy-chrysene, 2,3-benzofluorene, and benzo(a)pyrene may antagonize activity in yeast by binding to an anti-estrogen binding site on the hER or by mechanisms independent of the hER.
Binding, Competitive↗