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At least 631 records · Page 35Linked to original sources
PubMed1980

The disposition of aromatic hydrocarbons in adult spot shrimp (Pandalus platyceros) and the formation of metabolites of naphthalene in adult and larval spot shrimp.

1. Adult spot shrimp (Pandalus platyceros) exposed to 110 p.p.b. (microgram/ml) of the water-soluble fraction of Prudhoe Bay crude oil for one week accumulated a variety of low-molecular weight aromatic hydrocarbons (primarily C1-C5 substituted derivatives) in thoracic and abdominal tissues. 2. Adult and larval spot shrimp were exposed to 3H- and 14C- labelled naphthalene (a component of the water-soluble fraction) in seawater to delineate the types of metabolites formed. Both adults and larvae converted naphthalene to conjugated and non-conjugated structures such as the glucuronide, sulphate, dihydrodiol and phenolic derivatives. The presence of a quinone was also indicated.

Abdomen↗
PubMed1992

Inhibition of rat hepatic aryl sulphotransferase IV by dihydrodiol derivatives of benzo[a]pyrene and naphthalene.

1. Although neither the (+)- nor (-)-enantiomer of trans-benzo[a]pyrene-7,8-dihydrodiol was a substrate for aryl sulphotransferase IV from rat liver, both enantiomers inhibited the enzyme-catalysed sulphation of 1-naphthalene-methanol with Ki values of 3.7 +/- 0.4 microM for the (+)-enantiomer, and 4.4 +/- 0.3 microM for the (-)-enantiomer. 2. Based on the magnitude of the Ki values, the binding affinity of these dihydrodiols for the aryl sulphotransferase was significantly greater than that for the corresponding phenolic derivatives of benzo[a]pyrene. That is 7-hydroxybenzo[a]pyrene and 8-hydroxybenzo[a]pyrene were both substrates for aryl sulphotransferase IV, with apparent Km values of 280 +/- 41 microM and 370 +/- 72 microM, respectively. 3. Both (+)- and (-)-trans-naphthalene-1,2-dihydrodiols were also inhibitors of aryl sulphotransferase IV, but with higher Ki values than would be expected from previously determined apparent Km and Ki values for (R)-(-)- and (S)-(+)-1,2,3,4-tetrahydro-1-naphthols, respectively.

Animals↗
PubMed1995

Comparative disposition and biotransformation of naphthalene in fresh- and seawater-acclimated striped bass (Morone saxatilis).

1. The disposition and biotransformation of naphthalene in striped bass (Morone saxatilis) acclimated to either fresh- or seawater have been determined. 2. The 24-h total concentration factor did not significantly differ between the freshwater (283.7 +/- 61.5 [+/- SD]) and seawater (245.5 +/- 44.4)-acclimated bass. At both salinities, the viscera/gonad and liver accumulated large concentrations of residues, whereas the skin retained the largest total residue mass. 3. During the 24-h depuration period, the freshwater-acclimated bass depurated 45% of retained residue and the seawater-acclimated bass depurated 85% of retained residue. 4. Naphthalene was primarily excreted unchanged (> 99% in freshwater-acclimated bass and > 88% in seawater-acclimated bass), but small amounts of 1,2-dihydro-1,2-dihydroxynaphthalene and 1- and/or 2-naphthylsulphate were formed.

Animals↗
PubMedDate not supplied

[Growth of bacteria degrading naphthalene and salicylate at low temperatures].

A total of 58 bacterial strains degrading naphthalene and salicylate were isolated from soil samples polluted with oil products, collected in different regions of Russia during winter and summer. The isolates were assessed for their ability to grow at low temperatures (4, 8, and 15 degrees C); bacteria growing at 4 degrees C in the presence of naphthalene or salicylate accounted for 65% and 53%, respectively, of the strains isolated. The strains differed in the temperature dependence of their growth rates. It was demonstrated that the type of expression of Nah+ phenotype at low temperatures depended on the combination of the host bacterium and the plasmid.

Bacteria↗
PubMedDate not supplied

[New naphthalenic ligands of melatoninergic receptors].

Twenty three naphthalenic bio-isosteres of melatonin have been synthesized. The main structural variations concerned the acylamino substituents of the side chain and the alkoxy group on the 7-position of the naphthalene. Some of these compounds show greater affinity than melatonin itself for the melatonin receptor. The results of this study provide new informations on the structure affinity relationships and on the mode of interaction at the melatonin binding site.

Animals↗
PubMed2004

[Preliminary study on naphthalene-metabolites-albumin adduct as an exposure biomarker for coke oven workers].

OBJECTIVE: To study albumin adduct with naphthalene metabolites, namely 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ), as a potential biomarker for intermediate/long-term exposure to polycyclic aromatic hydrocarbons (PAH) in coke oven workers. METHODS: Twenty-eight coke oven workers and 22 control workers were recruited from a cokery. Spot urine and venous blood samples were collected from the workers after four continuously working days and personal information was obtained by questionnaire. Plasma albumin adduct was detected with gas chromatography-mass spectrometry. RESULTS: Albumin adduct with 1,2- & 1,4-NPQ (1,2-NPQ and 1,4-NPQ), respectively, were detected in all coke oven workers and controls. Median plasma level of 1,2-NPQ-Alb in coke oven workers was significantly higher than that in controls (76.6 pmol/g vs. 44.9 pmol/g, P < 0.01). However, there was no significant difference in plasma median level of 1,4-NPQ-Alb between the two groups (48.6 pmol/g vs. 44.2 pmol/g, P > 0.05). Plasma level of 1,2-NPQ-Alb was significantly higher than that of 1,4-NPQ-Alb in coke oven workers. Urine levels of naphthalene, 1-naphthol, 2-naphthol and 1-pyrenol in coke oven workers correlated significantly with their plasma level of 1,2-NPQ-Alb (Pearson coefficient of correlation greater than 0.371, P < 0.01), but did not do significantly with 1,4-NPQ-Alb. CONCLUSION: Plasma level of 1,2-NPQ-Alb could effectively reflect their magnitude of personal internal dose of exposure to air PAH, so it could be used as a potential biomarker to evaluate their intermediate/long-term exposure to PAH in coke oven workers.

Air Pollutants, Occupational↗
PubMed2004

Tissue distribution and elimination of selected chlorinated naphthalenes.

OBJECTIVES: Polychlorinated naphthalenes are widespread, persistent environmental pollutants. Commercial products are generally mixtures of several congeners and range from thin liquids to hard waxes of high melting point. The higher chlorinated naphthalene products are used as impregnants for condensers and capacitors and dipping encapsulating compounds in electronics. The aim of this study was to investigate the disposition of penta- and tetrachloronaphthalene in rats following a single intraperitoneal administration. MATERIALS AND METHODS: Experiments were performed on male Outbred Wist rats with body weight of 200-250 g. Both compounds labeled with tritium, were given intraperitoneally in a single dose of 10 mg/kg body weight. Blood and selected tissues distribution of 3H-radioactivity as well as urine and feces excretion from 0 to 336 h were traced following the administration. RESULTS: After 120 h about 70% of the given dose was excreted in feces. Feces proved to be the main route of tritium excretion; only about 6% were excreted in urine within 120 h. In all the examined tissues, the highest 3H concentrations were found in the fat tissue, liver, kidneys and adrenals. CONCLUSIONS: Following calculations of the balance of total tritium excreted and stored, it was found out that both chloronaphthalenes belong to compounds of slow turnover rate in the rat body, and especially in the case of repeated exposure they might accumulate in the body.

Animals↗
PubMedDate not supplied

9,10-Phenanthrenequinone photoautocatalyzes its formation from phenanthrene, and inhibits biodegradation of naphthalene.

Polycyclic aromatic hydrocarbons (PAHs) have earned considerable attention due to their widespread environmental distribution and toxicity. In the environment, PAHs decompose by a variety of biotic and abiotic pathways. In both polar and nonpolar environments, phenanthrene (Phe, a common, three-ring PAH) is converted by sunlight to more polar products such as 9,10-phenanthrenequinone (PheQ) and subsequent oxidation products such as the corresponding open-ring dicarboxylic acid product. Biodegradation of phenanthrene also usually leads to oxidative metabolites, and eventually ends in mineralization. Our experimental objective was to investigate the photodegradation of phenanthrene and determine the effect of reaction products such as PheQ on microbial biodegradation of two- and three-ring PAHs. Abiotic experiments were performed to examine the photolytic breakdown of Phe; Phe was converted to PheQ, which catalyzed its own formation. In biodegradation experiments PheQ (0.04-4 mg/L) caused marked inhibition of naphthalene (Nap) biodegradation by a Burkholderia species; Phe did not. Only 20% of the naphthalene was degraded in the presence of PheQ compared with 75% in the control culture with no PheQ added. No PAH-degrading cultures were able to use PheQ as sole carbon source; however, the Phe-degrading enrichment culture dominated by a Sphingomonas species was able to degrade PheQ cometabolically in the presence of Phe. These results may explain why photooxidized phenanthrene-containing mixtures can resist biodegradation.

Biodegradation, Environmental↗
PubMedDate not supplied

[Effect of transposons on expression of genes for naphthalene biodegradation in Pseudomonas putida BS202(NPL-1) and derivative strains].

NPL-1 and its derivative plasmid pBS106, which control the degradation of naphthalene and salicylate, were found to contain class II transposons of the Tn3 family. These transposons are involved in intraplasmid rearrangements, such as deletions and inversions, and can influence the expression of the catabolic and regulatory genes borne by biodegradation plasmids. The formation of a strong NahR-independent constitutive promoter by the inversion of a DNA fragment may be responsible for changing the character of naphthalene dioxygenase synthesis from inducible (in the case of plasmid NPL-1) to constitutive (in the case of plasmid NPL-41). The stability of plasmids NPL-1 and NPL-41 in the Pseudomonas putida strains grown on different substrates depends on the expression of the nah and tnp genes.

Base Sequence↗
PubMed1992

A support film of plasma-polymerized naphthalene for electron microscopy: method of preparation and application.

Methods of preparing of a new support film by plasma polymerization in a glow discharge, and its application were described. The recently developed plasma polymerization replica technique was used to prepare ultrathin films from naphthalene monomer gas on the surface of a newly cleaved sodium chloride crystal or on cover glass. The film was floated off on water or hydrofluoric acid solution to free it from the base. The plasma-polymerized naphthalene support film (PNS) prepared in this way was shown to have excellent properties by its application to negative staining of virus antigen particles and by the observation of whole ultrathin sections of animal tissue mounted on a 2 x 1 mm single slot grid. Features of the new support film are (1) its ease of preparation as a clean, very thin film of less than 10 nm, (2) its amorphous texture and high transparency to electrons, (3) its mechanical strength, resistance to heat and chemicals, and electron bombardment, and (4) its smooth and slightly hydrophilic surface. The PNS would be useful for both routine and high-resolution electron microscopy.

Animals↗
PubMed2006

Evidence of indigenous NAH plasmid of naphthalene degrading Pseudomonas putida PpG7 strain implicated in limonin degradation.

A well characterized naphthalene-degrading strain, Pseudomonas putida PpG7 was observed to utilize limonin, a highly-oxygenated triterpenoid compound as a sole source of carbon and energy. Limonin concentrations evidenced a 64% reduction over 48 h of growth in batch cultures. Attempts were made to acquire a plasmid-less derivative via various methods (viz. Ethidium Bromide, SDS, elevated temperature & mitomycin C), among which the method involving mitomycin C (20 ug/ml) proved successful. Concomitant with the loss of plasmid in P. putida PpG7 strain, the cured derivative was identified as a lim- phenotype. The lim+ phenotype could be conjugally transferred to the cured derivative. Based on the results of curing with mitomycin C, conjugation studies and presence of ndo gene encoding naphthalene 1,2 dioxygenase, it was demonstrated that genes for the limonin utilization were encoded on an 83 kb indigenous transmissible Inc. P9 NAH plasmid in Pseudomonas putida PpG7 strain.

DNA, Bacterial↗
PubMed1979

Absorption and metabolism of naphthalene and benzo(a)pyrene in the rat jejunum in situ.

Naphthalene or benzo(a)pyrene (100 nmol) was instilled into the closed rat intestinal loop in situ and the appearance of the free compound and its metabolites was determined in portal blood. Naphthalene appeared mostly unchanged in blood whereas benzo(a)pyrene was extensively metabolized by mucosal cells. The results suggest that absorption and metabolism are competing processes in the gut.

Animals↗
PubMedDate not supplied

[Effect of phospholipids on the activity of highly-purified liver microsome cytochrome P-450 in a reaction of aniline and naphthalene hydroxylation by hydroperoxides].

The effect of different phospholipids on the functional activity of highly purified cytochrome P-450 used as a co-substrate of cumene hydroperoxide was examined. At the molar ratio of phospholipids to cytochrome P-450 that was equal to 30, phosphatidyl serine, phosphatidyl inositol, the total fraction of microsomal phospholipids, and lysophosphatidyl choline increased the hydroxylation rate of aniline and naphthalene. The effect of the above phospholipids on the rate of naphthalene oxidation was much more pronounced. Phosphatidyl choline and sphingomyelin in similar large quantities did not exert a stimulating effect on the reactions studied. The kinetic parameters of aniline oxidation in the systems containing phospholipids that produced an activating effect were investigated.

Aniline Compounds↗
PubMed1995

Metabolism of [14C]naphthalene in the B6C3F1 murine isolated perfused liver.

Naphthalene (NA) is metabolized by pulmonary and hepatic tissues to epoxides, quinones, and their related phase II metabolites. To delineate specific liver metabolites, metabolism was studied in B6C3F1 mouse liver perfused with 5 and 10 mumol/hr [14C]NA. Liver metabolites were compared with urinary metabolites from mice exposed to an equivalent total dose of NA (50 mg/kg ip) to ascertain interorgan and extrahepatic transformation in vivo. Metabolites were separated into pools via hydrophobic columns under neutral (pool I) and acid (pool II) conditions. Pool I contained the majority of [14C] in perfusate and urine. In perfusate, high levels of sulfate conjugates of naphthol and dihydroxynaphthalene were found along with dihydrodiol and glucuronic acid conjugates. In the urine, dihydrodiol was the most abundant metabolite. A novel N-acetylated glutathione conjugate was a constituent of pool II of both perfusate and urine. Additional metabolites identified in urine were N-acetylcysteine conjugate of dihydrodiol epoxide, mercaptolactic acid conjugate of naphthalene oxide (NO), and diglucuronide and sulfate/glucuronide conjugates of dihydroxynaphthalene. Mercapturic acid conjugates of NO were not observed in either perfusate or urine; this finding highlights metabolic differences between strains. Differential covalent binding occurred in cellular fractions, with the highest binding occurring in microsomes and mitochondria. These metabolites indicate that interorgan metabolism plays a role in the disposition of NA in vivo.

Animals↗
PubMed1993

[Evaluation of exposure to benzene and naphthalene in coke plant workers].

Sixty two workers of a coke-chemical plant exposed to benzene, naphthalene, toluene, o-xylene, p-xylene, phenol and pyridine were examined. In urine samples collected before and after occupational exposure significant differences in concentration values of phenol (21.1-97.6 mg/l), 1--naphthol (0.1-9.38 mg/l), hippuric acid (95.5-873.9 mg/l) and m-methylhippuric acid (29.0-93.5 mg/l) were found. There was correlation between benzene and naphthalene in the breathing zone air and phenol and 1-naphthol in the urine of coke plant workers.

Air Pollutants, Occupational↗
PubMed1977

Morphology of a naphthalene-induced bronchiolar lesion.

Nonciliated bronchiolar epithelial (Clara) cells are selectively damaged by intraperitoneal administration of naphthalene. We examined these changes using light microscopy, transmission electron microscopy, and scanning electron microscopy. Naphthalene administration causes the Clara cells to expand and exfoliated shortly thereafter. Following exfoliation the remaining ciliated cells show morphologic abnormalities, including cilia loss and ballooning of remaining cilia. Upon regeneration of the Clara cells the ciliated cells gradually return to their normal appearance. One possible explanation for these findings is that the Clara cell secretions directly affect the physiologic state of the surrounding ciliated cells.

Animals↗
PubMed1996

Interindividual and interspecies variation in hepatic microsomal epoxide hydrolase activity: studies with cis-stilbene oxide, carbamazepine 10, 11-epoxide and naphthalene.

Microsomal epoxide hydrolase (HYL1) is a single-gene enzyme responsible for the hydrolysis of epoxides derived from the oxidative metabolism of xenobiotics. Variation in HYL1, therefore, may be an important determinant of drug toxicity. We have investigated HYL1 enzyme kinetics in six different species including man, for which a liver bank genotyped for polymorphisms in exons 3 and 4 of the HYL1 gene was used. Activity was measured by radiochromatography with high specific activity radiolabeled substrates, cis-stilbene oxide (CSO) and carbamazepine 10,11-epoxide (CBZ-E). In addition, naphthalene was used to investigate the hydrolysis of an epoxide (naphthalene 1,2-epoxide [N-E] generated in situ. There was marked species variation in enzyme activity that was substrate dependent. CSO was rapidly hydrolyzed by microsomes from all species, the rank order of specific activity being human > rabbit > dog > rat > hamster > mouse. In contrast, hydrolysis of CBZ-E was only observed with human liver microsomes. CBZ-E was only a weak (IC50 = 1 mM) inhibitor of CSO hydrolysis. The hydrolysis of N-E, determined as the diol-to-total metabolite ratio, was human > rabbit > dog > hamster > mouse > rat. Intraspecies variation in man was 4-fold, 7-fold and 2-fold for CSO, CBZ-E and N-E, respectively: none of this variation could be directly accounted for by the HYL1 polymorphisms in exons 3 and 4. These data emphasize the need for careful toxicokinetic evaluation of species used in the safety evaluation of compounds likely to form epoxide intermediates in vivo.

Adult↗
PubMed1999

1-anilino-8-naphthalene sulfonate as a protein conformational tightening agent.

1-Anilino-8-naphthalene sulfonate (ANS) anion is conventionally considered to bind to preexisting hydrophobic (nonpolar) surfaces of proteins, primarily through its nonpolar anilino-naphthalene group. Such binding is followed by an increase in ANS fluorescence intensity, similar to that occurring when ANS is dissolved in organic solvents. It is generally assumed that neither the negative sulfonate charge on the ANS, nor charges on the protein, participate significantly in ANS-protein interaction. However, titration calorimetry has demonstrated that most ANS binding to a number of proteins occurs through electrostatic forces, in which ion pairs are formed between ANS sulfonate groups and cationic groups on the proteins (D. Matulis and R. E. Lovrien, Biophys. J., 1998, Vol. 74, pp. 1-8). Here we show by viscometry and diffusion coefficient measurements that bovine serum albumin and gamma-globulin, starting from their acid-expanded, most hydrated conformations, undergo extensive molecular compaction upon ANS binding. As the cationic protein binds negatively charged ANS anion it also takes up positively charged protons from water to compensate the effect of the negative charge, and leaves the free hydroxide anions in solution thus shifting pH upward (the Scatchard-Black effect). These results indicate that ANS is not always a definitive reporter of protein molecular conformation that existed before ANS binding. Instead, ANS reports on a conformationally tightened state produced by the interplay of ionic and hydrophobic characters of both protein and ligand.

Anilino Naphthalenesulfonates↗