一株芽孢杆菌对多环芳烃的降解性能

从长期被焦化废水污染的污泥中分离出一株芽孢杆菌，它对蒽、菲、芘在单基质及混合基质条件下均有良好降解转化性能，在单基质条件下，起初的82h内，该菌株对蒽的降解转化效果最好，菲最差，反应进行到106h，各PAHs的浓度均接近于O；在混合基质条件下，菲的竞争代谢能力最强，芘最小；淘米水能明显促进单基质条件下芘的降解转化；在单基质蒽、菲、芘反应体系中，该芽孢杆菌能生长繁殖，菲存在下，细菌总数量大能增长到原加入量的16500倍，蒽存在下，相应的增加倍数为4120，含芘的体系中，则能增长到原加入量的920倍。     

PRELIMINARY FINDINGS THAT KEROSENE ALTERS THE DISTRIBUTION OF TOPICALLY APPLIED BENZO[A]PYRENE IN MICE

The dermal route is important in occupational exposure to polycyclic aromatic compounds (PACs), but other organs may be affected. We reported that kerosene-cleaning following treatment with used engine oil increased DNA adducts in the lungs of mice viz. animals treated with used oil alone. To determine the mechanism we topically applied ³ H-BAP(100 nmol in 25 μL acetone) and washed half the mice with 25 μL kerosene 1 h after carcinogen application. Groups of four mice were sacrificed from 1 to 72 h after treatment. Lung, liver, and skin were harvested. The fraction of the radiolabel remaining in the skin of animals treated with benzo[a]pyrene (BAP) and washed with kerosene was significantly less than those not washed, beginning at 24 h (p < .05). Fractional distribution to the lungs and livers of these animals became significantly elevated. Kerosene increased transdermal water loss. Kerosene treatment compromises dermal barrier function, enhances carcinogen absorption, and alters organ distribution.     

ALTERED MOBILITY OF BENZ[a]ANTHRACENE IN THE PRESENCE OF p-XYLENE AND ITS IMPACT ON RISK IN THE SUBSURFACE

Concerns over soil and groundwater contamination by PAHs have been raised as they are often introduced into the subsurface as nonaqueous-phase liquid (NAPL) mixtures. However, characterizing the risk posed by a mixture of chemicals is a challenging task due to its uncertainty in quantifying the effects of the interaction between substances. This study focuses on the effects of phase-transforming interaction on the fate, transport, and risk assessment of a PAH in a PAH - NAPL mixture. The cell test was carried out using benz[a]anthracene (BaA) and p-xylene to verify the increased mobility of highly sorbed pollutants in the presence of less sorbed, mobile liquid pollutants. The experimental results showed that BaA had greater mobility in the presence of p-xylene than in its absence. The main transport mechanisms in the vadose zone were by dissolution into p-xylene or water. The developed model showed that transport of BaA was significantly faster in the presence of NAPL, but needs improvement. As well, risk assessment indicated that the oral carcinogenic risk of BaA calculated with the concentration in groundwater was 15～ 87 times larger when mixed with NAPL than when present as a single contaminant. This study demonstrated that consideration of phase-transforming interaction is necessary to analyze the risk of a PAH - NAPL mixture. The improvement of the transport model will be the topic of our continuing research.     

TREND OF ATMOSPHERIC BENZO[ a ]PYRENE IN ITALY BEFORE THE ADOPTION OF THE EUROPEAN DIRECTIVE ON PAHs

The benzo[a]pyrene temporal trend was investigated in 11 towns where at least five annual means were available. The overall number of stations was 22, of which 12 were traffic-oriented, 6 background and 4 industrial. The trend was generally declining at traffic-oriented sites and roughly stable at background sites. The annual means in 2004 still exceeded the forthcoming European target value of 1 ng/m ³ in two towns (up to 1.9 ng/m ³ ). The background means (up to 1.4 ng/m ³ in 2004) accounted for approximately 40–90% of those at the traffic-oriented sites in the same town. The presence of a coke plant was incompatible with the attainment of the target value, while the adoption of technical measures on a carbon electrode plant was successful in attaining concentrations lower than the target value. In heavy traffic areas in Italy, the attainment of the target value hardly appears feasible under the current conditions of traffic congestion.     

COMPARATIVE METABOLISM OF PHENANTHRO[3,4-B]THIOPHENE,PHENANTHRO[4,3-B]THIOPHENE AND THEIR CARBON ANALOG BENZO[C]PHENANTHRENE BY RAT LIVER MICROSOMES

Phenanthro[3,4-b]thiophene (P[3,4-b]T) and phenanthro[4,3-b]thiophene (P[4,3-b]T) are thiasters of weakly mutagenic benzo[c]phenanthrene (B[c]P). These polycyclic sulfur heterocycles (thia-PAHs) represent a group of chemicals which have been identified in cigarette smoke. P[3,4-b]T is a potent mutagen in Salmonella typhimurium strain TA100 in the presence of rat liver S9, whereas its isosteric isomer P[4,3-b]T is a nonmutagenic compound. In order to understand the mechanism underlying the differences in the mutagenic activity of P[3,4-b]T and P[4,3-b]T, we have investigated the metabolism of P[3,4-b]T, P[4,3-b]T, and their carbon analogue B[c]P by rat liver microsomes. The liver microsomes from rats treated with Aroclor 1254 metabolized P[3,4-b]T, P[3,4-b]T, and B[c]P at a rate nearly 7- to 9-fold greater than of the control liver microsomes. High-performance liquid chromatography (HPLC) analysis of the metabolites formed showed that B[c]P was metabolized almost exclusively to its dihydrodiols which comprised predominantly K-region diol as noted in the previous studies. Our preliminary studies on the metabolism of P[3,4-b]T, P[4,3-b]T and B[c]P by liver microsomes from control and Aroclor 1254-treated rats have shown a significant reduction in the formation of 6,7-diol (K-region diol) and 8,9-diol (diol with a bay-region double bond) of the two thia-PAHs compared to the formation of analogous 5,6-diol (K-region diol) and 3,4-diol (diol with a bay-region double bond) from B[c]P. Both P[3,4-b]T and P[4,3b]T produced a major, relatively nonpolar metabolite(s) (80–96% of total metabolites). These studies indicate that the highly mutagenic P[3,4-b]T is not metabolized to dihydrodiol with a bay-region double bond to any greater extent than the weakly or nonmutagenic B[c]P or P[4,3-b]T, suggesting that the metabolite(s) other than P[3,4-b]T8,9-diol is likely to be involved in the mutagenicity of P[3,4-b]T.     

THE TOXICITY OF BENZO[a]PYRENE ON SOLE (SOLEA SOLEA) HEPATOCYTES: ASSESSMENT OF GENOTOXIC AND ENZYMATIC EFFECTS

The benzo[a]pyrene is a polycyclic aromatic hydrocarbon known to be genotoxic, mutagenic and carcinogenic in higher vertebrates. The aim of this study was to evaluate in vitro the enzymatic and genotoxic effects of BaP in a benthic fish species, Solea solea. Sole hepatocytes were exposed to BaP in order to measure the modulation of ethoxyresorufin-o-deethylase (EROD) activity and the DNA strand breaks induced by BaP metabolism. Exposures were performed in both culture flasks and microplate wells in order to check for the possible miniaturization of the exposure system. Moreover, sole liver microsomes were exposed to BaP in the presence of standard DNA in order to assess the potential formation of DNA adducts in sole. The results demonstrated the ability of sole hepatic enzymes to metabolize BaP into reactive species responsible for bulky DNA adducts and DNA strand breakage, whatever the tested exposure concentration and the mode of exposure.     

CERTIFIED CALIBRATION SOLUTION REFERENCE MATERIAL FOR THE DETERMINATION OF BENZO[A]PYRENE FROM THE NATIONAL METROLOGY INSTITUTE OF JAPAN (NMIJ)

A new calibration solution reference material (NMIJ CRM 4213-a) for benzo[a]pyrene (BaP) analysis was prepared and certified by the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). Certification of CRM 4213-a was carried out at NMIJ using a freezing point depression method and gravimetric preparation. Certified concentration of this CRM was obtained by multiplying the dilution ratio of raw material BaP in a prepared solution with purity of the raw material. Purity of our raw material was calibrated by a gas chromatograph with flame ionization detection using that of high-purity BaP purified by using a high performance liquid chromatograph with a normal phase column, because purity determination of the raw material by a differential scanning calorimeter (DSC) couldn't be assessed directly. The purity of high-purity BaP was assessed in the molar fraction by DSC, and then the purity of the mass fraction was calculated based on average molecular weight of impurities and the purity of the molar fraction. CRM 4213-a has been developed with a certified value of 99.2 mg/kg. Uncertainty was evaluated from purity assessment as well as homogeneity and stability of the CRM, and expanded uncertainty was estimated as 3.9 mg/kg with coverage factor k = 2, corresponding to an estimated confidence interval of approximately 95%.     

AN ISOTOPE DILUTION HIGH-RESOLUTION MASS SPECTROMETRY METHOD FOR QUANTITATIVE MEASUREMENT OF ISOMERIC BENZO[A]PYRENE TETROL METABOLITES DERIVED FROM ALBUMIN-BAPDE ADDUCTS AS INDICATORS OF HUMAN EXPOSURE TO POLYCYCLIC AROMATIC HYDROCARBONS

We evaluated in a pilot study a newly developed method of gas chromatography isotope dilution high-resolution mass spectrometry selected ion monitoring (GC-ID-HRMS-SIM). This method measures benzo[a]pyrene (B[a]P) tetrol metabolites released after albumin-BaPDE adduct hydrolysis. We isolated albumin adducts from the blood of a cohort of adult male and female smokers and nonsmokers randomly selected as exposed and nonexposed groups. Isomeric B[a]P tetrols released after adduct hydrolysis and silyl derivatization were quantified by GC-ID-HRMS-SIM using ¹³ C ₆ -isotopically labeled BaP tetrol isomer standards (+/?)-BaP-r-7,t-8,t-9,c-10-tetrol (BPTI-1), (+/?)-BaP-r-7,t-8,t-9,t-10-tetrol (BPTI-2), (+/?)-BaP-r-7,t-8,c-9,t-10-tetrol (BPTII-1) and (+/?)-BaP-r-7,t-8,c-9,c-10-tetrol (BPTII-2). In all donor samples analyzed the method was sensitive enough to detect BPTII-1 and BPTI-1 in the low fmol range. In both smokers and nonsmokers BPTI-1 levels were higher than BPTII-1 levels. The mean levels of BPTII-1 and BPTI-1 in smokers were 0.16 ± 0.04 fmol/mg albumin (ranging from 0.09 to 0.28 fmol/mg albumin) and 0.40 ± 0.06 fmol/mg albumin (ranging from 0.25 to 0.75 fmol/mg albumin), respectively. The mean levels of BPTII-1 and BPTI-1 in nonsmokers were 0.22 ± 0.07 fmol/mg albumin (ranging from 0.09 to 0.41 fmol/mg albumin) and 0.47 ± 0.06 fmol/mg albumin (ranging from 0.30 to 0.75 fmol/mg albumin), respectively. The results from this study are the first reported quantitative levels of specific benzo[a]pyrene tetrol isomers detected by isotope dilution high-resolution mass spectrometry measurements of BaPDE-albumin adducts using ¹³ C ₆ -isotopically labeled BaP tetrol isomer standards.     

MOLECULAR GEOMETRY,CYP1A GENE INDUCTION AND CLASTOGENIC ACTIVITY OF CYCLOPENTA[c]PHENANTHRENE IN RAINBOW TROUT

Cyclopenta[c]phenanthrene (CP[c]Ph) is a PAH member that shows similarities to bay-and fjord region possessing PAHs. On the basis of X-ray measurements it was found that the molecule of this hydrocarbon is planar. In this case, intramolecular strains caused by repulsion between protons in the pseudo fjord-region are balanced by both the shortening of some bonds which acquire more double bond character, and by the enlargement of exocyclic angles within the pseudo fjord-region. The activity of CP[c]Ph was investigated in vivo in rainbow trout, Oncorhynchus mykiss. The CYP1A mRNA levels following 48h-treatment with CP[c]Ph or benzo[a]pyrene (B[a]P; positive control) were determined and compared with incidences of clastogenic changes observed in the peripheral blood erythrocytes. We have found that the ability to induce CYP1A by these PAH compounds is positively correlated with the incidences of clastogenic changes in rainbow trout erythrocytes.     

DETERMINATION OF DIBENZO[A,L]PYRENE AND OTHER FJORD-REGION PAH ISOMERS WITH MW 302 IN ENVIRONMENTAL SAMPLES

Polycyclic aromatic hydrocarbons (PAHs) occur in the environment as complex mixtures including compounds with mutagenic and carcinogenic activity. The PAH profile routinely determined in environmental samples at present encompasses isomers with molecular weight (MW) not greater than 300. However, PAHs with MW >300 have been demonstrated for several matrices to contribute up to 50% of the total activity when tested for carcinogenicity in experimental animals. Recent studies indicate that among the dibenzopyrenes with MW 302 dibenzo[a,l]pyrene, possessing a fjord region, is by far the most carcinogenic PAH hitherto identified. To further elucidate the environmental relevance of this compound we have applied the isotope dilution GC/MS technique as analytical procedure to determine this compound and the related fjord region PAH naphtho[1,2-a]- and naphtho[1,2-e]pyrene in various matrices. Identification was based on comparison of UV and mass spectra as well as retention times of authentic reference materials. Determination of these PAHs was achieved after clean-up by several chromatographic steps including fractionation on a modified TABA-silica gel column. Quantitative data for matrices such as two cigarette smoke condensates, motor vehicle exhaust condensate (Otto-type engines), and tar-cork are reported. Based on toxic equivalent factors the relative contribution of dibenzo[a,l]pyrene (5.4–42.3%) to the total carcinogenic activity of a PAH profile will be discussed comprising 14 selected isomers (benzo[b]naphtho[2,1-d]thiophene; cyclopenta[cd]pyrene; benz[a]anthracene; chrysene/triphenylene; sum of benzo[b]-, benzo[k]-, and benzo[j]fluoranthene; benzo[a]pyrene; indeno[1,2,3-cd]pyrene; dibenz[a,h]anthracene; benzo[ghi]perylene; anthanthrene; dibenzo[a,l]pyrene determined in these matrices.     

MODELING AND OPTIMIZATION OF LACTIC ACID SYNTHESIS BY THE ALKALINE DEGRADATION OF FRUCTOSE IN A BATCH REACTOR

The present work deals with the determination of the optimal operating conditions of lactic acid synthesis by the alkaline degradation of fructose. It is a complex transformation for which detailed knowledge is not available. It is carried out in a batch or semi-batch reactor. The “Tendency Modeling” approach, which consists of the development of an approximate stoichiometric and kinetic model, has been used. An experimental planning method has been utilized as the database for model development. The application of the experimental planning methodology allows comparison between the experimental and model response. The model is then used in an optimization procedure to compute the optimal process. The optimal control problem is converted into a nonlinear programming problem solved using the sequencial quadratic programming procedure coupled with the golden search method. The strategy developed allows simultaneously optimizing the different variables, which may be constrained. The validity of the methodology is illustrated by the determination of the optimal operating conditions of lactic acid production.     

MODELING AND OPTIMIZATION OF LACTIC ACID SYNTHESIS BY THE ALKALINE DEGRADATION OF FRUCTOSE IN A BATCH REACTOR

The present work deals with the determination of the optimal operating conditions of lactic acid synthesis by the alkaline degradation of fructose. It is a complex transformation for which detailed knowledge is not available. It is carried out in a batch or semi-batch reactor. The “Tendency Modeling” approach, which consists of the development of an approximate stoichiometric and kinetic model, has been used. An experimental planning method has been utilized as the database for model development. The application of the experimental planning methodology allows comparison between the experimental and model response. The model is then used in an optimization procedure to compute the optimal process. The optimal control problem is converted into a nonlinear programming problem solved using the sequencial quadratic programming procedure coupled with the golden search method. The strategy developed allows simultaneously optimizing the different variables, which may be constrained. The validity of the methodology is illustrated by the determination of the optimal operating conditions of lactic acid production.     

DNA ADDUCTS OF BENZO[A]PYRENE- AND DIBENZO[A,L]PYRENE-DIOL EPOXIDES IN HUMAN LUNG EPITHELIAL CELLS: KINETICS OF ADDUCT REMOVAL,EFFECTS ON CELL CYCLE CHECKPOINTS,AND GENE EXPRESSION

The fjord-region PAH dibenzo[a,l]pyrene (DBP) is considerably more carcinogenic than the bay-region benzo[a]pyrene (BP). This fact can be ascribed to differences in DNA binding efficiency of their ultimate carcinogenic diol epoxide (DEs) intermediates, differences in structural features of the DNA adducts, and differences in DNA adduct recognition and the subsequent lesion removal by nucleotide excision repair (NER). In order to further substantiate previous findings in cell-free human systems (1 Buterin, T., Hess, M. T., Luneva, N., Geacintov, N. E., Amin, S., Kroth, H., Seidel, A. and Naegeli, H. 2000. Unrepaired Fjord Region Polycyclic Aromatic Hydrocarbon-DNA Adducts in Ras Codon 61 Mutational Hot Spots. Cancer Research, 60: 1849–1856.  [Google Scholar]), cultured cells (2 Luch, A., Kudla, K., Seidel, A., Doehmer, J., Greim, H. and Baird, W. M. 1999. The Level of DNA Modification by (+)-syn-(11S,12R,13S,14R)- and (?)-anti-(11R,12S,13S, 14R)-Dihydrodiol Epoxides of Dibenzo[a,l]pyrene Determined the Effect on the Proteins p53 and p21WAF1 in the Human Mammary Carcinoma Cell Line MCF-7. Carcinogenesis, 20: 859–865.  [Google Scholar]), and in rodents (3 Jankowiak, R., Ariese, F., Hewer, A., Luch, A., Zamzow, D., Hughes, N. C., Phillips, D., Seidel, A., Platt, K. L., Oesch, F. and Small, G. J. 1998. Structure, Conformations, and Repair of DNA Adducts from Dibenzo[a,l]pyrene: 32P-Postlabeling and Fluorescence Studies. Chemical Research in Toxicology, 11: 674–685.  [Google Scholar]) we have studied DNA adduct formation of anti-DE of DBP [(±)-anti-DBPDE], in A549 human epithelial lung carcinoma cells and monitored the levels of adducts as a function of time. A high-performance liquid chromatography (HPLC) procedure that allows monitoring of all cis- and trans-nucleoside adducts of dA and dG was used. Circular dichroism and UV-spectroscopy have been employed to gain information on adduct structural features. Incubation of cells with 0.1 μM (±)-anti-DBPDE resulted in rapid formation of adducts, followed by a decline. After 6 h of incubation about 20% of the adducts remained. Repeating the experiment with 0.01 μM (±)-anti-DBPDE resulted in a correspondingly lower adduct level initially, but in this case a larger proportion (35%) of the adducts remained after 6 h of incubation. Notably, at this time point, similar amounts of adducts are observed with both (±)-anti-DBPDE concentrations studied. Independent of diol epoxide concentration and incubation time, the dA/dG adducts were constant in number (～2.8). However, within the different adduct categories, the adduct distribution seemed to be time dependent. Although the data are preliminary, a selection with regard to adduct removal seems to have taken place. In comparative experiments with (+)-anti-BPDE, no significant difference in rates of adduct removal was evident. Preliminary results from global gene expression analysis, with focus on genes involved in DNA maintenance and cell cycle checkpoints, demonstrate interesting differences in the stress response elicited in the cells following exposure to the distorted and flexible nonplanar DBPDE or the rigid and planar BPDE molecule. As expected some major common induction events were clearly related to the activation of p53-dependent cell cycle checkpoint. However, distinct clusters of gene expression alterations were detected which mark one or other treatment specifically, indicating a high degree of subtlety in the stress response to closely related DNA adduct forming species.     

水溶性菁染料与类脂物混合单分子膜中J-聚集体形成的研究

报道了具有相同发色团,并有不同电荷的二种菁染料单分子膜中J-聚集体的形成。测定了单分子膜的π/A,△V/A曲线,反射光谱及吸收光谱。从实验结果得出:带正电荷的染料与花生酸混合形成单分子膜后,膜中染料的二聚体与J-聚集体随着表面压力改变存在着一个平衡。而带负电荷的染料与二十烷基胺成膜后,即使在很低的表面压下也有J-聚集体形成。同时染料分子在水面上的取向是各向异性。     

FORMATION OF BENZYLIC ALCOHOLS AND MESO-ALDEHYDES BY ONE-ELECTRON OXIDATION OF DMBA,A MODEL FOR THE FIRST METABOLIC STEP IN METHYLATED CARCINOGENIC HYDROCARBON ACTIVATION

The hypothesis that hydroxylation of the 7-methyl group is the first step in metabolic activation of 7,12-dimethylbenz[a]anthracene (DMBA) was advanced over three decades ago (1 Flesher, J. W. and Sydnor, K. L. 1971. Carcinogenicity of Derivatives of 7,12-Dimethylbenz[a]anthracene. Cancer Research, 31: 1951–1954. [PubMed], [Web of Science ®] , [Google Scholar], 2 Flesher, J. W. and Sydnor, K. L. 1973. Possible Role of 6-Hydroxymethylbenzo[a]pyrene as a Proximate Carcinogen of Benzo[a]pyrene and 6-Methylbenzo[a]pyrene. Int. J. Cancer, 11: 433–437.  [Google Scholar]). A considerable body of evidence supports the hypothesis (3 Flesher, J. W., Horn, J. and Lehner, A. F. 2002. The Meso-Region Theory of Aromatic Hydrocarbon Carcinogenesis. Polycyclic Aromatic Compounds, 22: 379–393. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). A chemical model for the oxidative metabolism of DMBA may be useful in understanding the mechanism of metabolic activation of DMBA and other methylated carcinogenic hydrocarbons, particularly the first step. Here we show that a nonenzymatic one-electron oxidation pathway transforms DMBA to carcinogenic alcohol and meso-aldehyde metabolites. The results are consistent with the hypothesis that hydroxylation of the 7-methyl and/or 12-methyl groups is the first metabolic step in DMBA activation. The hypothesis predicts that hydroxylation of other meso-methyl-substituted hydrocarbons is the first essential step in the metabolic activation of methylated carcinogenic hydrocarbons.     

A FACILE SYNTHESIS OF 11,12-DIMETHOXYDIBENZO[def,p]CHRYSENE,A PREFERRED PRECURSOR FOR THE SYNTHESIS OF THE PROXIMATE AND ULTIMATE CARCINOGENS OF DIBENZO[def,p]CHRYSENE (DBC)

A concise, convergent synthesis of 11,12-dimethoxydibenzo[def,p]chrysene (5), a preferred precursor for the synthesis of the carcinogenic metabolites of a highly potent carcinogen dibenzo[def,p]chrysene (DBC, 1) has been described. Suzuki cross-coupling reaction of 5,5-dimethyl-2-(3,4-dimethoxy-2-formyl)-1,3,2-dioxaborinane (6a) with 7-bromo-5,6-dihydro-4H-benz[de]anthracene (7) afforded 7-(2-formyl-3,4-dimethoxyphenyl)- 5,6-dihydro-4H-benz[de]anthracene (9). Treatment of 9 with an excess of potassium tert-butoxide produced 11,12-dimethoxydibenzo[def,p]chrysene (5) in overall 51% yield based on 6a.     

A STUDY OF H2SO4 FORMATION IN THE PROCESS OF SIMULTANEOUS SORPTION OF SO2, O2 AND H2O ONTO A SINGLE CARBON PARTICLE

A mathematical model to describe simultaneous sorption of SO₂, O₂ and H₂O in an activated carbon particle is presented in this paper. The competition for active sites of these species is taken into account by a modified Langmuir-type isotherm, which incorporates the competition of the immobile reaction product phase, H₂SO₄. Simulations of the model are presented in terms of transient micropore filling of reactant species and product H₂SO₄. The simulation results show that the multicomponent interactions play an important role in the sorption process. Fast diffusing species like O₂ and H₂O instantaneously adsorb in the micropore volume of the sorbent. In the course of simultaneous adsorption and reaction of all species in the micropore, a rollup phenomenon on the transient behavior of fast diffusing species could occur, i.e. the micropore loading of these gaseous species can overshoot the final equilibrium level. The simulation results of H₂SO₄ micropore loading are found to agree reasonably well with the experimental data.