Search results for "Pyrene"

Inactivation of electrophilic metabolites by glutathione S-transferases and limitation of the system due to subcellular localization

1977

Benzo(a)pyrene was activated to metabolites mutagenic for Salmonella typhimurium TA 98 by liver microsomes from control and phenobarbital treated mice. Under these conditions benzo(a)pyrene 4,5-oxide accounts for most of the mutagenicity. We have therefore investigated (1) the conjugation of benzo(a)pyrene 4,5-oxide with glutathione and (2) the effect of glutathione on the mutagenicity of benzo(a)pyrene.

The effect of dietary imbalances on the activation of benzo[a]pyrene by the metabolizing enzymes from rat liver.

1987

Abstract Male Sprague-Dawley rats (70–80 g) were fed ad libitum a standard control diet (22% casein, 5% lard), or a high lipid diet (30% lard) or a low protein diet (6% casein) or a standard diet containing 50 ppm phenoclor DP6. After 6 weeks on these diets, the cytochrome P-450 microsomal content, the benzo[ a ]pyrene monooxygenase (BaP-MO) and the epoxide hydrolase (EH) were assayed. The formation of mutagenic B(a)P metabolites which covalently bind with DNA was compared. The activity of BaP-MO and of EH were increased by the high lipid diet (+27% and 106% respectively) and by the phenoclor DP6 treatment (+63% and 400% respectively), compared to the standard diet. In animals fed a low pro…

The 3,4-oxide is responsible for the DNA binding of benzo[ghi]perylene, a polycyclic aromatic hydrocarbon without a “classic” bay-region

2008

Abstract The polycyclic aromatic hydrocarbon (PAH) benzo[ghi]perylene (BghiP) lacks a “classic” bay-region and is therefore unable to form vicinal dihydrodiol epoxides thought to be responsible for the genotoxicity of carcinogenic PAHs like benzo[a]pyrene. The bacterial mutagenicity of BghiP increases considerably after inhibition of the microsomal epoxide hydrolase (mEH) indicating arene oxides as genotoxic metabolites. Two K-region epoxides of BghiP, 3,4-epoxy-3,4-dihydro-BghiP (3,4-oxide) and 3,4,11,12-bisepoxy-3,4,11,12-tetrahydro-BghiP (3,4,11,12-bisoxide) identified in microsomal incubations of BghiP are weak bacterial mutagens in strain TA98 of Salmonella typhimurium with 5.5 and 1.5…

Sulfotransferase-mediated chlorination of 1-hydroxymethylpyrene to a mutagen capable of penetrating indicator cells.

1990

Methylated polycyclic aromatic hydrocarbons are common in the human environment. Many of them are stronger carcinogens than their purely aromatic congeners. They may be metabolized to benzylic alcohols. We report here on biochemical and toxicological characteristics of 1-hydroxymethylpyrene (HMP), a typical representative of this class of compounds. Rat liver cytosol, fortified with 3'-phosphoadenosine-5'-phosphosulfate, converted HMP into its sulfate ester (HMPS), HMPS bound covalently to isolated DNA. In physiological buffer at 37 degrees C, HMPS had a half-life of 2 min, the major decomposition product being HMP. Thus, cyclic activation is possible. When Cl- anions were present at physio…

Formation of mono- and diglucuronides and other glycosides of benzo(a)pyrene-3,6-quinol by V79 cell-expressed human phenol UDP-glucuronosyltransferas…

1995

Glucuronidation of quinols of polycyclic aromatic hydrocarbons (PAHs) represents an important detoxication pathway preventing toxic quinone/quinol redox cycles. Therefore, mono- and diglucuronide formation of benzo(a)pyrene-3,6-quinol was investigated and compared to that of structurally related 3,6-dihydroxychrysene and simple phenols (1-naphthol and 4-methylumbelliferone) using V79 cell-expressed human UGT1.6 (= P1) and human UGT1.7 (= P4). Properties of human UGT1.6 were compared to those of the rat ortholog. Cofactors related to UDP-glucuronic acid such as UDP-galacturonic acid and UDP-glucose were also studied. It was found that rat and human UGT1.6 and human UGT1.7 catalyse monoglucur…

Upper pleistocene interstratal piping-cave speleogenesis: The seso cave system (central pyrenees, northern spain)

2015

The Seso Cave System (SCS, South Central Pyrenees, Northeastern Spain) develops in poorly soluble marly interstratum between limestone beds of Eocene age. We propose an innovative and singular pseudokarstic speleogenetic model under vadose conditions based on cave morphological evidence, physicochemical and mineralogical characteristics of the Eocene marly host rock, U-Th dating of cave deposits, and local geological and geomorphological information. Eocene marls are shown to be sensitive to dispersion processes supported by their high clay content and the high concentration of sodium and low electrical conductivity in the seepage water. Runoff inside the cave results from water that infilt…

Thiophene pyrenyl derivatives for the supramolecular processability of single-walled carbon nanotubes in thin film heterojunction

2017

Abstract A major problem for the use of single-wall carbon nanotubes (SWCNTs) in electronic devices relates to their poor processability. Chemical modification inevitably introduces defects in the nanotube lattice, resulting in a loss of electronic properties. In this contest, we report on a supramolecular approach with the aim of increasing the dispersion of SWCNTs in solution and in organic semiconductor matrices by ensuring the optoelectronic properties. In particular, new pyrenyl derivatives of thiophene have been synthesized and used to improve the solubility of SWCNTs for electron transfer in thin film heterojunction with poly(3-hexylthiophene) (P3HT) as donor system. Photoinduced ele…

Supramolecular Design of Low-dimensional Carbon Nano-hybrids encoding a Polyoxometalate-bis-Pyrene Tweezer

2014

A novel bis-pyrene tweezer anchored on a rigid polyoxometalate scaffold fosters a unique interplay of hydrophobic and electrostatic supramolecular interactions, to shape carbon nanostructures (CNSs)-based extended architectures.

Layered Thiadiazoloquinoxaline-Containing Long Pyrene-Fused N-Heteroacenes

2018

Three thiadiazoloquinoxaline-containing long pyrene-fused N-heteroacenes with 8, 13, and 18 rings were designed and synthesized. They show high electron affinities (EAs) of approximately 4.1 eV, which were derived from the onset of the reduction peaks in cyclic voltammetry. Crystal structure analysis revealed in-plane extension through close contacts between thiadiazole units as well as layered packing, enabling in-plane and interlayer electron transport. Organic field-effect transistor devices provided electron mobilities, which suggest a potential way to enhance the charge transport in long N-heteroacenes.

2016

Two light-emitting polyphenylene dendrimers with both hole and electron transporting moieties were synthesized and characterized. Both molecules exhibited pure blue emission solely from the pyrene core and efficient surface-to-core energy transfers when characterized in a nonpolar environment. In particular, the carbazole- and oxadiazole-functionalized dendrimer (D1) manifested a pure blue emission from the pyrene core without showing intramolecular charge transfer (ICT) in environments with increasing polarity. On the other hand, the triphenylamine- and oxadiazole-functionalized one (D2) displayed notable ICT with dual emission from both the core and an ICT state in highly polar solvents. …