Glycine-β-cyclodextrin-assisted cometabolism of phenanthrene and pyrene by Pseudomonas stutzeri DJP 1 from marine sediment

Cometabolic degradation is currently an effective and extensively way to remove high molecular weight polycyclic aromatic hydrocarbons(HMW-PAHs).Unfortunately,due to low bio-accessibility and high biotoxicity,the cometabolic degradation rate of HMW-PAHs is limited.Glycine-β-cyclodextrin(GCD)was obtained through amino modification ofβ-cyclodextrin(BCD)and added to cometabolic system of phenanthrene(PHE)and pyrene(PYR)to assist PYR biodegradation.Results show that the addition of GCD(100 mg/L)effectively improved the removal rate of PYR(20 mg/L)by 42.3%.GCD appeared to increase the bio-accessibility and reduce the biotoxicity of PHE and PYR,and then promoted the growth of Pseudomonas stutzeri DJP1 and stimulated the elevation of dehydrogenase(DHA)and catechol 12 dioxygenase(C12O)activities.The phthalate metabolic pathway was accelerated,which improved the cometabolic degradation.This study provided a new reference for the cometabolic degradation of HMW-PAHs.

Determination of Benzo[a]pyrene in Edible Oil by High Performance Liquid Chromatography-Fluorescence Detector (HPLC-FL)

In this study, an optimized high performance liquid chromatography-fluorescence detector (HPLC-FL) method for the determination of benzo[a]pyrene in edible oil was established. HPLC was performed with Thermo Fisher Scientific C18 column (250 mm×4.6 mm, 5 μm) as the chromatographic column and acetonitrile and water as the mobile phase, and the excitation wavelength and emission wavelength of fluorescence detector were 286 and 430 nm, respectively. The response was high, and the linear range was 0.5-10.0 ng/ml. The lowest limit of detection was 0.11 ng/ml, and the average recovery was 92.5%. This method is suitable for quantitative analysis of benzo[a]pyrene content in edible oil.

Switch of phosphorylation to O-GlcNAcylation of AhR contributes to vascular oxidative stress induced by benzo[a]pyrene

Benzo[a]pyrene(B[a]P)is a food contaminant toxic for cardiovascular diseases.The nuclear translocation of Arylhydrocarbon receptor(AhR)plays an important role in B[a]P-induced oxidative stress and vascular diseases.We confi rmed that B[a]P promoted ROS production in vascular smooth muscle cells(VSMCs)in vitro and in vivo,associated with the nuclear translocation of AhR.It is known that phosphorylation inhibits while dephosphorylation of AhR promotes nuclear translocation of AhR.However,from the posttranslational modifi cation level,the mechanism by which B[a]P activates and regulates the nuclear translocation of AhR is unclear.Co-immunoprecipitation results showed that cytoplasmic AhR was phosphorylated before B[a]P stimulation,and switched to O-GlcNAcylation upon B[a]P 1-h stimulation in VSMCs,suggesting there may be a competitively inhibitory relationship between O-GlcNAcylation and phosphorylation of AhR.Next,siRNAs of O-linked N-acetylglucosamine transferase(OGT),O-GlcNAcase(OGA)and OGA inhibitor PUGNAc were used.SiOGT blocks but siOGA and PUGNAc promote B[a]P-dependent AhR nuclear translocation and oxidative stress.Ser11 may be the competitive binding site for phosphorylation and O-GlcNAcylation of AhR.Phosphorylation-mimic variant inhibits but O-GlcNAcylation of AhR promotes AhR nuclear translocation and oxidative stress.Our fi ndings highlight a new perspective for AhR nuclear translocation regulated by the competitive modifi cation between phosphorylation and O-GlcNAcylation.

Pyrene分子(小片石墨晶体)的电子传导特性(英文)

利用量子理论中基于Green函数的tight-binding方法,对pyrene分子的电子传导和电子流分布进行了理论研究。在考虑到界面耦合和Hopping积分的情况下,得出了电子透射谱和流分布的模拟结果。结果显示透射与电子的能量紧密相关;谱的振荡特征是能级量子化的结果;流分布有着特定的方向,并且在每一个原子点上符合Kirchhoff量子流守恒定律。另外还发现了桥接pyrene分子的正负能开关特性。

Identification of 1-hydroxypyrene in urine of dogs after pyrene injection and its excretion

With high performance liquid chromatograph and fluorospectrometry, 1-hydroxypyrene is identified as a metabolite of pyrene in the urine of dogs after intramuscular injection of pyrene. When three successive doses of 1,2 and 5 μmol/kg wt. pyrene administered, urinary excretion of 1-hydroxypyrene reaches the peak level between 24th and 48th hours. Excreted 1-hydroxypyrene consists of only about 0.05% of injected pyrene.

FLUOROMETRIC METHOD FOR RAPID DETECTION OF DNA DAMAGE IN HUMAN PERIPHERAL LEUKOCYTES INDUCED BY BENZO(A)PYRENE

A preliminary study on application of Pluorometric Analysis ofDNA Unwinding（FADU）to the detection of DNA strand breaksinduced by indirect environmental mutagen benzo（a）pyrene（BaP）was conducted.The results showed that BaP,activated by PCB-in-duced rat liver S9mixture,could result in obvious increase of DNAstrand breaks in human peripheral leukocytes incubated with

DFT Study of Monochlorinated Pyrene Compounds

The structure, electronic properties, and chemical reactivity of pyrene and its three monochlorinated derivatives have been theoretically studied by using density functional theory (DFT). Several methods and basis sets are tested for the optimization of the geometrical structure and the B3LYP/6-311G** method/basis set is found to be the most suitable in predicting the heat of formation of pyrene and the minimum energy optimized structure of pyrene and its monochlorinated derivatives. The geometrical parameters and the heat of formation of pyrene are in good agreement with available experimental data. The chemical reactivity and stability of the four compounds are investigated. The computed results agree well with experimental results of monochlorination of the pyrene molecule. The relative stability of the monochlorinated pyrene compounds is in the order: 1-chloropyrene > 4-chloropyrene > 2-chloropyrene.

Water solubility enhancements of pyrene by single and mixed surfactant solutions

Water solubility enhancements of pyrene by both single surfactant and mixed surfactant solutions were compared and evaluated. The solubility of pyrene in water was greatly enhanced by each of Triton X 100 (TX100), Triton X 405 (TX405), Brij 35 and SDS, in which the water solubility enhancements increased with increasing surfactant concentrations. The extent of solubility enhancements at surfactant concentrations below the CMC is the order of TX100>Brij 35>TX405>SDS; the sequence at surfactant concentrations above the CMC is TX100>Brij 35>SDS>TX405. Pyrene was solubilized synergistically by anionic nonionic mixed surfactant solutions, especially at low surfactant concentrations. The synergistic power of the mixed surfactants is SDS TX405>SDS Brij 35>SDS TX100. The synergism as noted is attributed to increasing Kmc and/or decreasing the CMC of the mixed surfactant solution. For SDS TX405 and SDS Brij 35 mixed surfactant solutions, an increase in Kmc is coupled with a decrease in the CMC; for SDS TX100, only a decreased in the CMC value is noted. Mixed surfactant solutions may improve the performance of the surfactant enhanced remediation (SER) of soils by increasing the bioavailability and biodegradation of non aqueous phase organic pollutants and reducing the level of surfactant pollution and remediation expenses.

Inhibitory effects of RRR-α-tocopheryl succinate on benzo (a) pyrene (B (a) P)-induced forestomach carcinogenesis in female mice

AIM To study the inhibitory effects of VES( RRR-α-tocopheryl Succinate, VES ), aderivative of natural Vitamin E, on benzo (a)pyrene (B (a) P)-induced forestomach tumor infemale mice.METHODS The model of B (a)P-inducedforestomach tumor was established according tothe methods of Wattenberg with slightmodifications. One hundred and eighty femalemice (6 weeks old) were divided into six groupsequally; negative control (Succinic acid),vehicle control ( Succinate + B (a) P), positivecontrol(B(a) P), high VES(2.5g/kg. b. w + B(a)P), Iow VES(1 .25 g/kg. b. w + B(a) P) ig as wellas VES by ip (20 mg/kg, b. w + B(a) P). Exceptthe negative control group, the mice wereadministrated with B(a)P ig. and correspondingtreatments for 4 weeks to study the anti-carcinogenetic effect of VES during the initiationperiod. The experiment lasted 29 weeks, inwhich the inhibitory effects of VES both ontumor incidence and tumor size were tested.RESULTS The models of B (a)P-inducedforestomach tumor in female mice wereestablished successfully. Some werecauliflower-like, others looked like papilla, evena few were formed into the ulcer cavities. VES at1.25 g/kg. b. w, 2.5 g/kg. b.w. by ig and 20 mg/kg. b. w. via ip could decrease the number oftumors per mouse (1.7 ± 0. 41, 1.6 ± 0.34 and 1.1±0.43), being lower than that of B(a)P group(5.4 ± 0.32, P＜0.05). The tumor incidence wasinhibited by 18.2%, 23.1% and 50.0%. VES at1.25g/kg.b.w., 2.5 g/ kg.b.w. by ig and20 mg/kg. b.w. via ip reduced the total volumeof tumors per mouse (54.8 ± 8.84, 28.4 ± 8.32and 23.9± 16.05), being significantly lower thanthat of B(a)P group (150.2±20.93, P＜0.01).The inhibitory rates were 63.5%, 81.1% and84.1%, respectively.CONCLUSION VES has inhibitory effects on B(a) P-induced forestomach carcinogenesis infemale mice, especially by ip and it may be apotential anti-cancer agent in vivo.

n-Hexadecane and pyrene biodegradation and metabolization by Rhodococcus sp. T1 isolated from oil contaminated soil

The high-molecular weight polycyclic aromatic hydrocarbons(PAHs) pyrene and typical long chain alkane nhexadecane are both difficult to degrade. In this study, n-hexadecane and pyrene degrading strain Rhodococcus sp. T1 was isolated from oil contaminated soil. Strain T1 could remove 90.81% n-hexadecane(2 vol%) and 42.79% pyrene(200 mg·L^(-1)) as a single carbon within 5 days, respectively. Comparatively, the degradation of pyrene increased to 60.63%, but the degradation of n-hexadecane decreased to 87.55% when these compounds were mixed. Additionally, identification and analysis of degradation metabolites of Rhodococcus sp. T1 in the above experiments showed that there were significant changes in alanine, methylamine, citric acid and heptadecanoic acid between sole and dual substrate degradation. The optimal conditions for degradation were then determined based on analysis of the pH, salinity, additional nutrient sources and liquid surface activity.Under the optimal conditions of pH 7.0, 35 °C, 0.5% NaCl, 5 mg·L^(-1) of yeast extract and 90 mg·L^(-1) of surfactant,the degradation increased in single or dual carbon sources. To our knowledge, this is the first study to discuss metabolite changes in Rhodococcus sp. T1 using sole substrate and dual substrate to enhance the long-chain alkanes and PAHs degradation potential.

Conjugate Fluorescent Compound Based on Pyrene-imidazole: Design, Synthesis, Crystal Structure and Fluorescence Property

Pyrenes are an important group of polycyclic aromatic hydrocarbons(PAHs). In order to expand the diversity of conjugate compounds based on pyrene, two new isomeric compounds anti-PyDTPAI and syn-PyDTPAI containing pyrene, imidazole and triphenylamine are synthesized via a one-pot cyclization reaction and characterized. The anti-PyDTPAI is characterized by single-crystal X-ray diffraction which crystallizes in monoclinic, space group P2_1/n with a = 10.132(4), b = 14.997(7), c = 18.968(9) ?, β = 95.543(19)o, V = 2869(2) ?~3, Z = 2, F(000) = 1092, Dc = 1.196 Mg/m^3, Mr = 1033.28 and μ(Mo Kα) = 0.070 mm^(-1). The presence of intermolecular C–H···π interactions results in the stability of the compound. The crystal structure shows a centrosymmetric, coplanar configuration towards pyrene-imidazole segment and a slip-stacked packing mode across the longer molecular axis which is similar to the J-type aggregation. The investigation of UV-vis absorption and fluorescence in solution indicates a strong blue emission under the ultraviolet light excitation. The two isomers also display high thermal stability which is proved by differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA). Additionally, the molecular structure and HOMO and LUMO levels are calculated by density functional theory(DFT) at the B3 LYP/6-31 G(d) level.

Preliminary Characterizations of a Carbohydrate from the Concentrated Culture Filtrate from <i>Fusarium solani</i>and Its Role in Benzo[a]Pyrene Solubilization

In order to investigate the mechanism of benzo[a]pyrene uptake by a filamentous fungus Fusarium solani, a biochemical characterization of its concentrated culture filtrate has been conducted. The preparation contained approximately (w/w): 50% of total carbohydrate, 6.5% of uronic acid and 6% protein, as determined by colorimetric tests. Gel filtration and anion-exchange chromatographic profiles indicated that the main product of the culture filtrate was a glycoprotein, which contained mannose, glucose and galactose in an approximate molar ratio of 1.5: 0.8: 1. The polysaccharide fraction of the culture filtrate was prepared by treatment with proteinase K, followed by gel-filtration chromatography. Its chemical structure was studied by methylation analysis, gas-liquid chromatography-mass spectrometry (GC-MS) and Nuclear Magnetic Resonance spectroscopy (NMR). The major carbohydrate was a polymer of β-(1 → 6)-linked galactofuranose units fully branched at positions O-2 by single residues of α-glucopyranose. The Fusarium concentrated culture filtrate increased 4-fold the BaP solubilization in comparison with its aqueous solubility and suggested that the carbohydrate present in this filtrate should probably be involved in this enhancement. Our findings point out the potential role of fungal glycoproteins in PAH microbial bioavaibility, an important step for PAH biodegradation.

LASER FLASH SPECTROSCOPY STUDIES OF PYRENE EXCIMER IN ACETONITRILE

Formation and decay processes of pyrene excimer in acetonitrilehave been measured by laser flash spectroscopy at 475nm,and thedependence of λ1+λ2 on the pyrene concentration has also been measured at290°K.On the basis of these measurements,six rate parameters whichdescribe the behaviour of pyrene excimer system in acetonitrile solutionhave been evaluated.At 355 nm laser light irradiation,the ΔG of thepyrene excimer formation in acetonitrile is evaluated to be -30.18kJ/mol.This value is quite different from the corresponding ΔG in cyclohexane（-16.72kJ/mol）.

A NEW KIND OF SURFACTANT:LONG-CHAIN ALKYLTRIPHENYLPHOSPHONIUM HALIDES Ⅲ.AN“ABNORMAL”QUENCHING OF PYRENE FLUORESCENCE BY PHOSPHONIUMS WITH DIFFERENT LENGTHS OF ALKYL CHAIN

A study of the quenching of pyrene fluorescence by a series of alkyltriphenylphosphonium bromides indi-cated the coiling conformation of ionic surfactant in aqueous solution.Formation of pyrene excimer in cetyltriph-enylphosphonium solution strengthened the conclusion.

Transcriptomic Response of Nannochloropsis oceanica to Benzo[a]pyrene

In this study, the RNA sequencing was used to describe the response of Nannochloropsis oceanica, a marine microalga, to benzo[a]pyrene(BaP), a polycyclic aromatic hydrocarbon, in order to elucidate the metabolic pathways(or processes) involved in microalgal response to this stubborn pollutant. N. oceanica was exposed to BaP at a concentration of 90 μg L^-1 for 72 h, and its transcriptome was sequenced through the Illumina HiSeq^TM 2500 platform. This concentration of BaP was selected as it is the lowest for modeling the most appropriate growth inhibition of N. oceanica for transcriptomic analysis. We found that N. oceanica responds to BaP through degrading proteins and repairing DNA damaged by BaP. In addition, superoxide dismutase(SOD) strengthened its performance by increasing its transcript abundance. The physiological mechanism underlining the response of N. oceanica to BaP as revealed by transcriptomic analysis was consistent with the biochemical insights documented previously.

mRNA expression of CYP4 in marine polychaete Marphysa sanguinea in response to benzo[a]pyrene

Rapid amplification of cDNA ends (RACE) and real-time polymerase chain reaction (RT-PCR) were carried out to analyze the CYP4 gene expression in polychaete Marphysa sanguinea exposed to benzo[a]pyrene (BaP) in this study. The full length of MsCYP4 cDNA was 2 470 bp, and it encoded 512 amino acids. The deduced amino acid sequence showed 47% identity with CYP4F from frog Xenopus tropicalis and shared high homology with other known CYP4 sequences. To analyse the role of CYP4 in protecting M. sanguinea from BaP exposure, three BaP groups were established: 0.5, 5 and 50 μg/L. Polychaetes were sampled after 3, 7 and 12 d. At 0.5 μg/L, the effect of BaP on MsCYP4 gene expression increased with time prolonged. MsCYP4 gene expression curve showed Ushaped trend with time in 5 and 50 μg/L BaP groups. Therefore, MsCYP4 gene may play an important role in maintaining the balance of cellular metabolism and protecting M. sanguinea from BaP toxicity.

L－519，A PHENOLIC COMPOUND，INHIBITS METABOLISM OF BENZO（a）PYRENE AND MUTAGENESIS INDUCED BY BENZO（a）PYRENE

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Characteristics of copper removal and ion release during copper biosorption by Stenotrophomonas maltophilia in presence of benzo[a]pyrene

The ability of Stenotrophomonas maltophilia was demonstrated to selectively remove Cu2+from Cu(NO3)2 solution under the circumstance that 1 mg/L benzo[a]pyrene(BaP) was either present or not. The removal ratios of 2 and 10 mg/L Cu2+by 0.25 g/L biosorbent are up to 80% and 49% at 10 min, respectively. The biosorption includes ion exchange, NO3 reduction, ion release, and cell oxidation by Cu2+. BaP does not significantly affect Cu2+removal and ion release. Although 2 mg/L Cu2+increases the release of PO4 3, K+, NH4 +and Ca2+, 10 mg/L Cu2+has strong oxidation on cell, and then decreases NO3 reduction and hinders the release of K+, NH4 +and Ca2+. Exogenous cations inhibit the Cu2+biosorption, while additional anions increase the removal ratios of 10 mg/L Cu2+from 52% to 88%.

A pyrene-based ratiometric fluorescent probe with a large Stokes shift for selective detection of hydrogen peroxide in living cells

Hydrogen peroxide(H2O2)plays a significant role in regulating a variety of biological processes.Dysregulation of H2O2 can lead to various diseases.Although numerous fluorescent imaging probes for H2O2 have been reported,the development of H2O2 ratiometric fluorescent probe with large Stokes shift remains rather limited.Such probes have shown distinct advantages,such as minimized interference from environment and improved signal-to noise ratio.In this work,we reported a new pyrene-based compound Py-VPB as H2O2 fluorescent probe in vitro.The probe demonstrated ratiometric detection behavior,large Stokes shift and large emission shift.In addition,the probe showed high sensitivity and selectivity towards H2O2 in vitro.Based on these excellent properties,we successfully applied Py-VPB to the visualization of exogenous and endogenous H2O2 in living cells.Cell imaging study also showed that our probe was localized in the mitochondria.We envision that the probe can provide a useful tool for unmasking the biological roles of mitochondrial H2O2 in living systems.

RELATIONSHIP BETWEEN ACTIVITIES OF CYTOCHROME P-450 MONOOXYGENASES IN HUMAN PLACENTAL MICROSOMES AND BINDING OF BENZO(A)PYRENE METABOLITES TO CALF THYMUS DNA.

Benzo(a)pyrene metabolism in human placental microsomes fromsmokers was studied.Benzo(a)pyrene metabolites were separatedusing high pressure liquid chromatographic technique. Reactionof benzo(a)pyrene with microsomal fraction of placenta fromindividuals who smoke cigarette during pregnency yields 7。