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At least 19 recordsLinked to original sources
PubMed1999

Development of toxicity criteria for petroleum hydrocarbon fractions in the Petroleum Hydrocarbon Criteria Working Group approach for risk-based management of total petroleum hydrocarbons in soil.

The Total Petroleum Hydrocarbon Criteria Working Croup (TPHCWG) was formed in 1993 based on the observation that widely different clean-up requirements were being used by states at sites that were contaminated with hydrocarbon materials such as fuels, lubricating oils, and crude oils. These requirements were usually presented as concentration of total petroleum hydrocarbon (TPH), and ranged from 10 to over 10,000 mg TPH/kg soil. Members of this multi-disciplinary group, consisting of representatives from industry, government and academia, jointly recognized that the numerical standard was not based on a scientific assessment of human health risk and established the following goal for the effort: To develop scientifically defensible information for establishing soil cleanup levels that are protective of human health at hydrocarbon contaminated sites. The approach developed by the TPHCWG for TPH hazard assessment consisted of dividing the petroleum hydrocarbon material into multichemical-containing fractions with similar fate and transport characteristics. These fractions were then assigned fate and transport properties (volatilization factor, soil leaching factor, etc.) and toxicity values (RfDs/RfCs) representative of the fraction. The actual site specific hazard assessment and derivation of cleanup levels is accomplished by analyzing sites to determine which fraction(s) is present and applying the appropriate fate, transport and toxicity factors. The method used by this group to determine TPH Faction specific toxicity criteria is a surrogate approach intended to supplement the indicator approach. Indicators are single, carcinogenic hydrocarbon compounds which are evaluated/regulated individually at either the federal or state level. The TPHCWG surrogate approach utilized all appropriate fraction specific toxicity data (single compound and mixture/product), minus the carcinogenic indicator compounds, to derive the fraction specific RfDs and RfCs. This hazard assessment method for petroleum contaminated sites would be utilized where indicator compounds are not present or are below/remediated to regulatory action levels. Derivation of the RfD/RfC values for the n-hexane containing aliphatic C5-C8 fraction is examined in detail to illustrate the underlying assumptions and use of existing data employed by the TPHCWG to develop fraction specific toxicity criteria. Toxicity RfDs/RfCs for all of the model fate and transport based fractions are also presented.

Animals↗
PubMed1997

Determination of aryl hydrocarbon receptor nuclear translocator protein concentration and subcellular localization in hepatic and nonhepatic cell culture lines: development of quantitative Western blotting protocols for calculation of aryl hydrocarbon receptor and aryl hydrocarbon receptor nuclear translocator protein in total cell lysates.

Western blot analysis was used to determine the concentration of the aryl hydrocarbon receptor nuclear translocator (ARNT) protein and aryl hydrocarbon receptor (AHR) in 11 mammalian cell culture lines derived from hepatic and nonhepatic tissues. The strategy was to first use Western blot analysis to determine the expression of ARNT or AHR in each cell line relative to its concentration in murine wild-type Hepa-1c1c7 (Hepa-1) cells. Actual ARNT and AHR concentrations in known amounts of total cell lysates were then determined by generating a standard curve with defined amounts of a highly purified ARNT or AHR protein and performing regression analysis. The results show that the level of ARNT expression in each of the cell lines is similar and represents approximately 0.001-0.002% of total cellular protein. The range of expression was only approximately 3-fold with wild-type Hepa-1 cells expressing the highest level of ARNT (33,000/cell) and canine kidney cells (MDCK line) expressing 14,000 ARNT molecules/cell. In contrast, the concentration of AHR varied by 65-fold over the different cell lines with the wild-type Hepa-1 expressing 323,000 AHR/cell and rat hepatoma cells (H4IIE) expressing 4700. The ratio of AHR to ARNT ranged from 0.3 in H4IIE cells to 10 in the Hepa-1 line with the majority of cells expressing 1-5 times more AHR than ARNT protein. Immunocytochemical staining of each cell line showed that ARNT was exclusively localized to the nuclear compartment and that a conserved nuclear localization signal mapped to the NH-terminal portion of the protein.

Amino Acid Sequence↗
PubMed1978

Biochemical activation of aryl hydrocarbon hydroxylase activity, cellular distribution of polynuclear hydrocarbon metabolites, and DNA damage by polynuclear hydrocarbon products in human cells in vitro.

Carcinogenic polynuclear hydrocarbons [7,12-dimethylbenzanthracene, 3-methylcholanthrene, and benzo(a)pyrene] were added to human skin fibroblast cell cultures. Only benzo(a)pyrene at 10 microgram/ml or above induced mixed-function hydroxylase activity, altered cell proliferation kinetics, and caused DNA damage as measured by altered grain count and bromodeoxyuridine incorporation. 3-Methylcholanthrene at concentrations as high as 15 microgram/ml was ineffective. 7,12-Dimethylbenzanthracene at 6 microgram/ml or above induced mixed-function oxygenase and stimulated DNA synthesis and cell proliferation, but at those concentrations little or no cytotoxicity or DNA damage was detected. The noncarcinogenic analogs 6,8,12-trimethylbenzanthracene, 5-fluorodimethylbenzanthracene, anthracene, and phenanthrene had no detectable effect on the human cells. It was concluded that benzo(a)pyrene can initiate all the biochemical events in human cells probably necessary to initiate transformation of human cells in vitro.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1977

Assimilation of liquid hydrocarbon by microorganisms. I. Mechanism of hydrocarbon uptake.

The uptake mechanism of liquid hydrocarbons of low solubility in water was investigated, using microorganisms with different affinities for liquid hydrocarbon. Microorganisms which could utilize hydrocarbon were much more adherent to hydrocarbon than those which could not. The adhesive force between Candida intermedia IFO 0761 and hydrocarbon was higher than that of Candida tropicalis ATCC 20336, though both could utilize hydrocarbon; The total hydrocarbon uptake from the drop and accommodation forms of hydrocarbons was much higher than that from dissolved hydrocarbon. The uptake rate of drop-form hydrocarbon was nearly equal to that of accommodation-form hydrocarbon for C. intermedia, but was lower for C. tropicalis which shows lower adhesion to hydrocarbon.

Adsorption↗
PubMed1982

Interaction of polycyclic hydrocarbons with cytochrome P-450. I. Specific binding of various hydrocarbons to P-448(1).

Interaction of various polycyclic aromatic hydrocarbons with P-448(1) from rabbit liver microsomes was demonstrated by measuring absorption, CD and fluorescence spectra of the hydrocarbons, the cytochrome and the complexes of both. On binding of hydrocarbons such as pyrene and benz[a]anthracene to P-448(1), prominent CD peaks appeared at around the wavelengths where the hydrocarbons possess absorption bands. Correspondingly, fluorescence of the hydrocarbons was quenched to various extents depending on the hydrocarbon examined but was restored when the protein structure was destroyed by denaturation. The absorption peaks of the bound hydrocarbons also shifted toward a longer wavelength. Such an appearance of CD bands, quenching of fluorescence emission or a shift of absorption peaks was not seen when the hydrocarbons were mixed with P-450(1) or albumin. Titration experiments indicated that hydrocarbons can bind specifically and tightly to P-448(1) at a single binding site to form equimolar complexes. Complexes of 21 kinds of hydrocarbons, possessing 2 to 5 benzene rings spread in various directions, were isolated and their spectral properties were investigated. It was shown that the hydrocarbons bind to P-448(1) at the same site and compete with one another. Evidence was obtained that the hydrocarbons were bound at the substrate site in the heme-containing domain of the monooxygenase, P-448(1), and metabolized by the aid of NADPH-cytochrome P-450 reductase in the presence of NADPH and O2.

Animals↗
PubMed1982

Interaction of polycyclic hydrocarbons with cytochrome P-450. III. Effects of hydrocarbon binding on the interaction of some ligands with P-448(1) heme.

The binding of polycyclic hydrocarbons to P-448(1) affected the interaction of exogenous ligands, such as ethyl isocyanide and CO in the ferrous state and 1-methyl imidazole in the ferric state, with the heme to various extents depending on the structure of the hydrocarbons. The effect of the hydrocarbons on dissociation constants (Kd) on the three ligands was essentially similar. Kd of ethyl isocyanide and CO for hydrocarbon-free P-448(1) were 18 microM and 1.1 microM, respectively. The affinities of both the ligands increased about 3-fold when hydrocarbons of a small molecular size, such as phenanthrene, were bound to P-448(1). Addition of a benzene ring to the outside of the phenanthrene molecule resulted in a remarkable decrease in the affinities of both the ligands. The binding of larger hydrocarbons in size produced a stronger inhibitory effect on the interaction of ethyl isocyanide with P-448(1). Thus, Kd of the isocyanide for benz[a]anthracene-bound and dibenz[a,c]anthracene-bound P-448(1) were estimated to be 260 microM and 3 mM, respectively. Spectral changes hardly occurred on addition of 4 mM ethyl isocyanide to 3-methylcholanthrene-bound or 7,8-benzoflavone-bound P-448(1). The effect of the hydrocarbon binding on Kd of the ligands was depressed when a benzene ring which links two aromatic rings in the hydrocarbon molecule was replaced by a single C-C bond. A probable structure of the active area of P-448(1) composed of the substrate site and the heme is proposed based on the effect of the hydrocarbon binding on the interaction between the exogenous ligands and the P-448(1) heme iron reported in this series of papers. The binding of hydrocarbons to P-448(1) increased the intensity ratio of the 430 nm to the 453 nm peak of the absorption spectrum of the ethyl isocyanide compound. When a large and long hydrocarbon in shape such as dibenz[a,h]anthracene was bound to P-448(1), a red shift of the Soret absorption peak and modification of the Soret CD pattern of the CO compound were observed.

Animals↗
PubMed1978

Distribution of hydrocarbon-utilizing microorganisms and hydrocarbon biodegradation potentials in Alaskan continental shelf areas.

Hydrocarbon-utilizing microorganisms were enumerated from Alaskan continental shelf areas by using plate counts and a new most-probable-number procedure based on mineralization of (14)C-labeled hydrocarbons. Hydrocarbon utilizers were ubiquitously distributed, with no significant overall concentration differences between sampling regions or between surface water and sediment samples. There were, however, significant seasonal differences in numbers of hydrocarbon utilizers. Distribution of hydrocarbon utilizers within Cook Inlet was positively correlated with occurrence of hydrocarbons in the environment. Hydrocarbon biodegradation potentials were measured by using (14)C-radiolabeled hydrocarbon-spiked crude oil. There was no significant correlation between numbers of hydrocarbon utilizers and hydrocarbon biodegradation potentials. The biodegradation potentials showed large seasonal variations in the Beaufort Sea, probably due to seasonal depletion of available nutrients. Non-nutrient-limited biodegradation potentials followed the order hexadecane > naphthalene >> pristane > benzanthracene. In Cook Inlet, biodegradation potentials for hexadecane and naphthalene were dependent on availability of inorganic nutrients. Biodegradation potentials for pristane and benzanthracene were restricted, probably by resistance to attack by available enzymes in the indigenous population.

Alaska↗
PubMed2001

Analysis of interleukin-8 release from normal human epidermal keratinocytes exposed to aliphatic hydrocarbons: delivery of hydrocarbons to cell cultures via complexation with alpha-cyclodextrin.

While inhalation exposures represent the predominant route for jet fuel toxicity, increased concern has been placed on topical exposures due to reports of severe contact dermatitis among military personnel. All three of the predominant aviation fuels currently used by the commercial and military sectors have been demonstrated experimentally to induce the production of interleukin-8 (IL-8), a proinflammatory cytokine, in normal human epidermal keratinocytes (NHEK). The objective of this study was to examine the effects of individual hydrocarbon components found in these fuels on IL-8 production by NHEK. In order to circumvent the extreme hydrophobicity of these compounds, inclusion complexes were formed between alpha-cyclodextrin/aliphatic hydrocarbons by adding 2 mM hydrocarbons to 4 mM alpha-cyclodextrin. NHEK were exposed to four aliphatic hydrocarbons (undecane, dodecane, tridecane, hexadecane) for 24 h at concentrations of 7.8-500 microM. These hydrocarbons caused a peak in IL-8 release at a concentration of 31.2 microM, with the exception of dodecane which peaked at 62.5 microM. Subtoxic concentrations of the aliphatic hydrocarbons were those < 62.5 microM. These studies demonstrate that the etiology of proinflammatory cytokine expression due to jet fuel exposure may be due in large part to the aliphatic hydrocarbon components. Furthermore, these studies provide additional evidence that hydrocarbons can be successfully delivered to cells in culture by encapsulating them in cyclodextrin inclusion complexes.

Cells, Cultured↗
PubMed1973

Aliphatic hydrocarbons of Cladosporium resinae cultured on glucose, glutamic acid, and hydrocarbons.

The carbon source markedly influenced the qualitative and quantitative composition of cellular hydrocarbons in Cladosporium resinae. Total lipid and hydrocarbon content was greater in cells grown on n-alkanes than in cells grown on glucose or glutamic acid. Glucose-grown cells contained a spectrum of aliphatic hydrocarbons from C(7) to C(36); pristane and n-hexadecane comprised 98% of the total. Cells grown on glutamic acid contained C(7) to C(23) hydrocarbons; n-tridecane, n-tetradecane, n-hexadecane, and pristane made up 74% of the total. n-Decane-grown cells yielded C(8) to C(32) compounds, and n-hexadecane (96%) was the major hydrocarbon. Cells grown on individual n-alkanes from C(11) to C(15) all contained C(11) to C(28) hydrocarbons, and cells grown on n-hexadecane contained C(11) to C(32) hydrocarbons. In n-undecane-grown cells, n-hexadecane and pristane made up 92% of the total, but in cells grown on C(12) to C(16)n-alkanes the major cellular hydrocarbon was the one on which the cells were grown. This suggests that cells cultured on n-alkanes of C(12) or longer accumulate n-alkanes prior to oxidizing them.

Alkanes↗
PubMed1979

The association of bacterial mutagenicity of hydrocarbon-derived 'bay-region' dihydrodiols with the Iball indices for carcinogenicity and with the extents of DNA-binding on mouse skin of the parent hydrocarbons.

The mutagenic activities of benz[alpha]anthracene, 7-methylbenz[alpha]anthracene, 7,12-dimethylbenz[alpha]anthracene, 3-methylcholanthrene and benzo[alpha]pyrene, together with those of the trans-dihydrodiols derived from these hydrocarbons that would be expected to yield 'bay-region' vicinal diolepoxides on further metabolism have been examined in assays with S. typhimurium TA100 using post-mitochondrial supernatant fractions prepared from the livers of 3-methylcholanthrene-treated rats. Mutagenic activities obtained have been compared with: (a) the extents of reaction with DNA that occur in mouse skin following treatment with these hydrocarbons; (b) the carcinogenicities of the hydrocarbons expressed as Iball indices; (c) their activities as tumour-initiating agents on mouse skin. Close positive associations were found between the microsome-mediated mutagenicities of the dihydrodiols that could yield "bay-region" diol-epoxides and: (a) the extents of reaction with DNA in hydrocarbon-treated mouse skin; (b) the carcinogenic potencies of the parent hydrocarbons; although these correlations are not perfect, the mutagenic activities of the hydrocarbons themselves in microsome-mediated assays with S. typhimurium show no correlation with their extents of DNA binding on mouse skin and a poor correlation with their activities as initiating agents. These comparisons also indicated a statistically-significant positive correlation between carcinogenicity and the in vivo DNA binding on mouse skin treated with the hydrocarbons. Differences in the metabolic pathways by which polycyclic hydrocarbons are activated in vivo and in vitro are discussed in relation to the improved correlations found with the dihydrodiols.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

Characterization of CYP1B1 and CYP1A1 expression in human mammary epithelial cells: role of the aryl hydrocarbon receptor in polycyclic aromatic hydrocarbon metabolism.

CYP1B1 and CYP1A1 expression and metabolism of 7,12-dimethylbenz(a)anthracene (DMBA) have been characterized in early-passage human mammary epithelial cells (HMECs) isolated from reduction mammoplasty tissue of seven individual donors. The level of constitutive microsomal CYP1B1 protein expression was donor dependent (<0.01-1.4 pmol/mg microsomal protein). CYP1B1 expression was substantially induced by exposure of the cells to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to levels ranging from 2.3 to 16.6 pmol/mg among the seven donors. Extremely low, reproducible levels of constitutive CYP1A1 expression were detectable in three donors (0.03-0.16 pmol/mg microsomal protein). TCDD inductions were larger for CYP1A1, as compared to CYP1B1, demonstrating substantial variability in the induced levels among the donors (0.8-16.5 pmol/mg). Northern and reverse transcriptase PCR analyses corroborate the donor-dependent differences in protein expression, whereby CYP1B1 mRNA (5.2 kb) was constitutively expressed and was highly induced by TCDD (33-fold). The contributions of CYP1B1 and CYP1A1 to the metabolism of DMBA were analyzed using recombinant human CYP1B1 and CYP1A1, as references, in conjunction with antibody-specific inhibition analyses (anti-CYP1B1 and anti-CYP1A1). Constitutive microsomal activity exhibited a profile of regioselective DMBA metabolism that was characteristic of human CYP1B1 (increased proportions of 5,6- and 10,11-DMBA-dihydrodiols), which was inhibited by anti-CYP1B1 (84%) but not by anti-CYP1A1. TCDD-induced HMEC microsomal DMBA metabolism generated the 8,9-dihydrodiol of DMBA as the predominant metabolite, with a regioselectivity similar to that of recombinant human CYP1A1, which was subsequently inhibited by anti-CYP1A1 (79%). A CYP1B1 contribution was indicated by the regioselectivity of residual metabolism and by anti-CYP1B1 inhibition (25%). DMBA metabolism analyses of one of three donors expressing measurable basal expression of CYP1A1 confirmed DMBA metabolism levels equivalent to that from CYP1B1. The HMECs of all donors expressed similar, very high levels of the aryl hydrocarbon receptor and the aryl hydrocarbon nuclear translocator protein, suggesting that aryl hydrocarbon receptor and aryl hydrocarbon nuclear translocator protein expression are not responsible for differences in cytochrome P450 expression. This study indicates that CYP1B1 is an important activator of polycyclic aromatic hydrocarbons in the mammary gland when environmental chemical exposures minimally induce CYP1A1. Additionally, certain individuals express low levels of basal CYP1A1 in HMECs, representing a potential risk factor of mammary carcinogenesis through enhanced polycyclic aromatic hydrocarbon bioactivation.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2004

Adsorption and conversion of various hydrocarbons on monolithic hydrocarbon adsorber.

Adsorption and conversion of various hydrocarbons on monolithic hydrocarbon adsorbers were studied using a new experimental model, temperature-programmed adsorption (TPA). In this study, methyl alcohol, acetone, acetaldehyde, 2,2,4-trimethylpentane, n-octane, and toluene were chosen as model hydrocarbons for cold start of a vehicle. The effect of the hydrocarbon components and oxygen concentration on the TPA curve was investigated. Depending on the presence of O(2), the adsorbed and desorbed amounts of the hydrocarbons were decreased, while the conversion efficiency of the hydrocarbons was increased. In the case of hydrocarbons containing oxygen, the thermal decomposition appeared to be in the order methanol, acetaldehyde, and acetone.

Journal Article↗
PubMed2001

Membranous nephropathy, hydrocarbon exposure and genetic variants of hydrocarbon detoxification.

Modulation of biotransformation by genetic traits may be important in determining environmentally-induced nephrotoxicity. We conducted a case-control study to investigate the role of occupational hydrocarbon exposure, along with polymorphisms of the genes coding for N-acetyltransferase 2 (NAT2) and glutathione S-transferase mu (GSTmu), in the development of idiopathic membranous glomerulonephritis (IMGN). Patients (n=36) with biopsy-proven IMGN were matched with healthy controls for age, gender, and geographical area. Lifetime hydrocarbon exposure was assessed by a validated questionnaire. The polymorphisms of the NAT2 and GSTmu genes (GSTM1) were defined by use of a polymerase chain reaction on white-cell DNA from peripheral blood. Exposure to hydrocarbons was significantly greater in patients with IMGN than in controls (mean+/-SEM hydrocarbon exposure score 11 003+/-2955.7 vs. 4352+/-1418, p<0.02). NAT2 acetylator status was identical in patients and controls with 23 (63.9%) fast and 13 (36.1%) slow acetylators in each group. GSTmu was present in 15 (41.7%) patients and 16 (44.4%) controls. While occupational exposure to hydrocarbons remains a likely factor in its pathogenesis, further work is required to identify the genetic polymorphisms that modulate the risk of IMGN.

Arylamine N-Acetyltransferase↗
PubMed2004

Effects of hydrocarbon structure on fatty acid, fatty alcohol, and beta-hydroxy acid composition in the hydrocarbon-degrading bacterium Marinobacter hydrocarbonoclasticus.

The lipids of the gram-negative bacterium Marinobacter hydrocarbonoclasticus grown in a synthetic seawater medium supplemented with various hydrocarbons as the sole carbon source were isolated, purified, and their structures determined. The hydrocarbons were normal, iso, anteiso, and mid-chain branched alkanes, phenylalkanes, cyclohexylalkanes, and a terminal olefin. According to the sequential procedure used for lipid extraction, three pools were isolated: unbound lipids extracted with organic solvents (corresponding to metabolic lipids and to the main part of membrane lipids), OH- labile lipids [mainly ester-bound in the lipopolysaccharides (LPS)], and H+ labile lipids (mainly amide-bound in the LPS). Each pool contained FA, fatty alcohols, and beta-hydroxy acids. The proportions of these lipids in the unbound lipid pools were 84-98%, 1.1-11.6%, and 0.1-3.6% (w/w), respectively. The chemical structures of the lipids were strongly correlated with those of the hydrocarbons fed; analytical data suggested a metabolism essentially through oxidation into primary alcohol, then into FA and degradation via the beta-oxidation pathway. Sub-terminal oxidation of the hydrocarbon chains, alpha-oxidation of FA or double-bond oxidation in the case of the terminal olefin, were minor, although sometimes substantial, routes of hydrocarbon degradation. Cyclohexyldodecane did not support growth, likely because of the toxicity of cyclohexylacetic acid formed in the oxidation of the alkyl side chain. In the OH- and H+ labile lipid pools, beta-hydroxy acids, the lipophilic moiety of LPS, generally dominated (28-72% and 64-98%, w/w, respectively). The most remarkable feature of these cultures on hydrocarbons was the incorporation in LPS of beta-hydroxy acids with Codd, omega-unsaturated, iso, or anteiso alkyl chains in addition to the specific beta-hydroxy acid of M. hydrocarbonoclasticus, 3-OH-n-12:0. These beta-hydroxy acids were tolerated insofar as their geometry and steric hindrance were close to those of the 3-OH-n-12:0 acid.

Alteromonadaceae↗
PubMed2004

Cuticular hydrocarbon dynamics in young adult Polistes dominulus (Hymenoptera: Vespidae) and the role of linear hydrocarbons in nestmate recognition systems.

In social insects, cuticular hydrocarbons (CHCs) play an important role in nestmate discrimination processes, but young individuals are usually not discriminated. We studied CHC changes in young workers of the social wasp Polistes dominulus. A quantitative estimation demonstrated that total quantities of CHCs increased after emergence, with branched alkanes increasing drastically when compared with other classes of hydrocarbons. The relative quantity of longer-chain compounds increased with respect to shorter ones; unsaturated compounds decreased. These changes might reduce the capacity of the cuticle to acquire compounds of environmental origin. We then tested whether individuals acquire hydrocarbons from the environment, and whether this capability equally characterises newly emerged and mature wasps. We exposed wasps of two age classes (adults younger or older than 24 h) to four linear hydrocarbons in turn, and observed how nestmates reacted to their re-introduction into the natal colony. Exposed young wasps elicited significantly more aggressive responses than control sisters; but treated wasps older than 24 h were generally accepted by nestmates. Chemical assays showed that exposed young wasps readily absorbed hydrocarbons; older ones did not incorporate hydrocarbons, suggesting that the chemical profiles of mature wasps are less prone to chemical shifts than those of newly emerged wasps.

Alkanes↗