Metabolism of naphthalene to naphthalene dihydrodiol glucuronide in isolated hepatocytes and in liver microsomes.
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Animals↗
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[Naphthalene oxidation by a Pseudomonas putida strain carrying a mutant plasmid].
Naphthalene oxidation by a parent and a mutant strain of Pseudomonas putida was studied. The parent strain contained a plasmid NPL-1 which controlled oxidation of naphthalene to salicylic acid and was capable of oxidizing salicylate. The mutant strain did not oxidize salicylate because of a mutation in salicylate hydroxylase; it contained also a mutant plasmid NPL-41 which determined constitutive synthesis of naphthalene oxygenase. Salicylic acid which accumulated as a product of naphthalene catabolism in the cultural broth of the wild strain was found to undergo further oxidation by the population of growing cells. The content of salicylic acid in the cultural broth of the mutant strain reached maximum and then remained constant. An anion-exchange resin was tested in order to prevent the inhibition of naphthalene oxygenase by salicylate and to increase the yield of salicylic acid. The transmissible character of the mutant plasmid NPL-41 makes it possible, with the aid of conjugation, to construct Pseudomonas strains which would oxidize naphthalene to salicylic acid without further degradation of this compound.
Culture Media↗
Distribution and elimination of naphthalene and 2-methylnaphthalene in rainbow trout during short- and long-term exposures.
The accumulation and elimination of 14C in rainbow trout tissues following short- and long-term exposures to aqueous 14C-naphthalene or 14C-2-methylnaphthalene were studied. After exposure for eight hr to 0.005 mg/L or 0.023 mg/L of 14C-naphthalene most tissues of fingerling rainbow trout studied contained 14C at 20 to 100 times the water levels while fat and bile contained 14C at several hundred times water levels. The half-lives for elimination of 14C from all tissues except fat were less than 24 hr. Exposure of fingerling rainbow trout to 14C-naphthalene or 14C-2-methylnaphthalene for four weeks in a continuous-flow delivery system resulted in maximum tissue levels of these chemicals of from 40 to 300 times the water concentration. Maximum bile 14C levels were 13,000 and 23,500 times the water concentration for 14C-naphthalene and 14C-2-methylnaphthalene exposure, respectively. Elimination of 14C accumulated from 14C-naphthalene in this long-term exposure was much slower than after short-term exposures, while elimination of 14C accumulated from 14C-2-methylnaphthalene was biphasic. The presence of parent compounds and metabolites in acetone extracts of muscles was determined by TLC. The data suggest that the biphasic release of 14C from muscle of trout exposed to 14C-2-methylnaphthalene may be due to differential elimination of parent compound and metabolites.
Animals↗
Glutathione and mercapturic acid conjugations in the metabolism of naphthalene and 1-naphthyl N-methylcarbamate (carbaryl).
The formation of glutathione (GSH) conjugate in the detoxification of [1-14C]-naphthalene and [naphthyl-14C]-carbaryl was investigated using rat liver homogenate. The mercapturic acid conjugate in rats was also investigated by collection of urine after intraperitoneal injection of 14C substrates. The formation of water-soluble metabolites in vitro from naphthalene was dependent on the amount of glutathione added, but this was not seen in carbaryl metabolism. In vitro, the metabolism of [1-14C]-naphthalene produced 50% GSH conjugates in the incubation mixture, whereas in vivo the metabolism of this compound produced 65% mercapturic acid conjugate in the urine. There was no evidence of GSH or mercapturic acid conjugate in the metabolism of [naphthyl-14C]-carbaryl in vitro and in vivo. This conclusion was made by comparing the nature and chemical characteristics of GSH and mercapturic acid conjugates formed in [1-14C]-naphthalene metabolism. With the aid of the specific enzyme (e.g. beta-glucuronidase and sulfatase) and acid hydrolysis, the water-soluble metabolites of [naphthyl-14C]-carbaryl were tentatively recognized as glucuronide or sulfate conjugated mainly with 5,6-dihydro-5,6-dihydroxycarbaryl or N-hydroxy-methyl carbaryl and their hydrolytic products. This data demonstrated that the substituent group on the naphthalene molecule may affect the significance of GSH conjugation.
Acetylcysteine↗
Studies on the binding of 1-anilino-8-naphthalene sulfonate to very low density and high density himan serum lipoproteins.
Very low density and high density lipoproteins have been isolated from human plasma and their interaction with 1-anilin0-8-naphthalene sulfonate has been studied under different conditions of pH and added salt. Intrinsic fluorescence of bound 1-anilino-8-naphthalene sulfonate was higher for high density lipoproteins then for very low density lipoproteins, but was unaffected by salt in both systems. Binding of 1-anilino-8-naphthalene sulfonate by both these lipoproteins was saturable and was higher in the presence of added NaCl or CaCl2, Ca2+ having a greater effect than Na+ in enhancing fluorescence. The binding data were analyzed by Scatchard plots; the number of binding sites and the affinity of 1-anilino-8-naphthalene sulfonate for the site increased with increasing salt concentration. Fluorescence pH curves were similar to those published for phospholipids. From these and previous observations it is suggested that the phospholipids probably represent the major binding sites for 1-anilino-8-naphthalene sulfonate.
Anilino Naphthalenesulfonates↗
Initial reactions in the oxidation of naphthalene by Pseudomonas putida.
A strain of Pseudomonas putida that can utilize naphthalene as its sole source of carbon and energy was isolated from soil. A mutant strain of this organism, P. putida 119, when grown on glucose in the presence of naphthalene, accumulates optically pure (+)-cis-1(R),2(S)-dihydroxy-1,2-dihydronaphthalene in the culture medium. The cis relative stereochemistry in this molecule was established by nuclear magnetic resonance spectrometry. Radiochemical trapping experiments established that this cis dihydrodiol is an intermediate in the metabolism of naphthalene by P. Fluorescens (formerly ATCC, 17483), P. putida (ATCC, 17484), and a Pseudomonas species (NCIB 9816), as well as the parent strain of P. putida described in this report. Formation of the cis dihydrodiol is catalyzed by a dioxygenase which requires either NADH or NADPH as an electron donor. A double label procedure is described for determining the origin of oxygen in the cis dihydrodiol under conditions where this metabolite would not normally accumulate. Several aromatic hydrocarbons are oxidized by cell extracts prepared from naphthalene-grown cells of P. putida. The cis dihydrodiol is converted to 1,2-dihydroxynaphthalene by an NAD+-dependent dehydrogenase. This enzyme is specific for the (+) isomer of the dihydrodiol and shows a primary isotope effect when the dihydrodiol is substituted at C-2 with deuterium.
Culture Media↗
Solubilization as a method for studying self-association: solubility of naphthalene in the bile salt sodium cholate and the complex pattern of its aggregation.
Solubilization of uncharged, slightly soluble solutes is shown to be a useful approach for investigating patterns of self-association. The solubility of naphthalene in aqueous solutions of sodium cholate was determined over the concentration range of 0-0.20 mole/liter at 25 degrees. Bile salts such as sodium cholate have many detergent-like properties and exhibit hydrophobic self-association in aqueous solutions. It has become cutomary to describe this aggregation using the model of micelle formation. The naphthalene solubility data show that the CMC for sodium cholate is not well defined. Comparison with solubilization in a typical micelle-forming system, sodium decanesulfonate, shows clearly that sodium cholate does not resemble a micelle-forming system. Further examination of the solubility data in terms of mutual association of naphthalene with aggregate species shows that the self-association of sodium cholate is not consistent with the formation of (a) only large micelles containing 10 or more monomers, (b) only dimers, (c) dimers and large micelles, and (d) any unique oligomer or multimer. A complex pattern of association, including the formation of dimers and one or more higher oligomers, is indicated.
Chemical Phenomena↗
Fungal transformation of naphthalene.
Eighty-six species of fungi belonging to sixty-four genera were examined for their ability to metabolize naphthalene. Analysis by thin-layer and high pressure liquid chromatography revealed that naphthalene metabolism occurred in forty-seven species belonging to thirty-four genera from the major fungal taxa. All organisms tested from the order Mucorales oxidized naphthalene with species of Cunninghamella, Syncephalastrum and Mucor showing the greatest activity. Significant metabolism was also observed with Neurospora crassa, Claviceps paspali and four species of Psilocybe. The predominant metabolite formed by most organisms was 1-naphthol. Other products identified were, 4-hydroxy-1-tetralone, trans-1,2-dihydroxy-1,2-dihydronaphthalene, 2-naphthol, 1,2-and 1,4-naphthoquinone.
Chromatography, High Pressure Liquid↗
Methylthio metabolites of naphthalen excreted by the rat.
Eight methylthio metabolites have been found as urinary products of the metabolism of naphthalene in the rat. One was 1-methylthionaphthalene. A second was a methylthio analog and the dihydrodiol, and a third was naphthalene substituted with one hydroxyl and one methylthio group. Two compounds with common structural elements were found; one of these was prepared by synthesis from anti-1,2:3,4-naphthalene dioxide and one from 1 beta, 2 alpha-dithyroxy-3 alpha, 4 alpha-epoxy-1,2,3,4-tetrahydronaphthalene by reaction with 2-keto-4-methylthiobutyric acid or with methionine. Each of these compounds contained one methythio group and three hydroxyl groups substituted on a tetrahydronaphthalene structure. Two metabolites with two methylthio groups and two hydroxyl substituents on a tetrahydronaphthalene ring were also detected; one of these was prepared by synthesis from the dioxide. The most likely metabolic origin of these methylthio metabolites is through the reaction of epoxides (including the diepoxide) with a nucleophile which may be methyl mercaptan, 2-keto-4-methylthiobutyric acid, or methionine.
Animals↗
Formation in vivo of deuterated methylthio metabolites of naphthalene from L-methionine (methyl-d--3).
Studies were carried out with deuterated methionine (methyl-d--3) to determine if methylthio metabolites of naphthalene were formed in vivo by reaction with methionine-derived metabolites. Rats were maintained on a methionine-free diet for nine days followed by eight days on the same diet supplemented with L-methionine-d--3 prior to administration of naphthalene. When naphthalene metabolites isolated from urine were characterized by GC and GC-MS procedures, it was found that the incorporation of deuterium into the methylthio metabolites, as well as into a catechol methyl ether, was approximately 40%. These results show that the methyl group was derived from methionine.
Animals↗
On the nature of the energised state of submitochondrial particles; investigations with N-aryl naphthalene sulphonate probes.
1. A further investigation has been made of the way in which the fluorescent probes 1-anilino-naphthalene-8-sulphonate and 2-(N-methyl-anilino) naphthalene-6-sulphonate report on the energised state of bovine heart submitochondrial particles. 2. A comparison of the probe responses to energisation with ATP or to a potassium diffusion potential has been made. The fluorescence enhancements seen in these two cases have different characteristics, and in view of this it is questioned whether a substrate generated energised state of a submitochondrial particle can be equated with a trans-membrane potassium diffusion potential. 3. Substitution of ITP for ATP reduces the rate at which either of the probes respond to energisation. In contrast reducing the ATPase activity of the particles by treatment with the covalent ATPase inhibitors 4-chloro-7-nitrobenzofurazan or N,N'-dicyclohexyl-carbodiimide has no effect on this rate. This finding that the rate of the fluorescence changes is directly sensitive to events at the level of the ATPase, but not to the total ATPase activity, suggests that this rate may not be controlled by a delocalised energised state. Reduction of ATPase activity decreases the extent of the fluorescence enhancement and a relationship between the change in probe fluorescence and ATPase activity is given. 4. The results in this paper are discussed in the context of the mechanisms which have been proposed to account for the fluorescence enhancements of N-aryl naphthalene sulphonate probes upon energisation of submitochondrial particles.
Adenosine Triphosphatases↗
Hepatic mixed-function oxidase activity in mice treated with methylated benzenes and methylated naphthalenes.
Eight methylated benzene and five methylated naphthalene compounds were injected ip into adult male mice daily for 3 days. On the fourth day livers from control and treated mice were compared with regard to weight, microsomal N- and O-demethylase activity, and various spectral characteristics of microsomal cytochrome P-450. Three methylated benzenes and one methylated naphthalene produced significant increases in liver weight/body weight ratios, O-demethylation of p-nitroanisole, N-demethylation of aminopyrene, or a combination of these.
Animals↗
Metabolism of naphthalene by Cunninghamella elegans.
Cunninghamella elegans grown on Sabouraud dextrose broth in the presence of naphthalene produced six metabolites. Each product was isolated and identified by conventional chemical techniques. The major metabolites were 1-naphthol (67.9%) and 4-hydroxy-1-tetralone (16.7%). Minor products isolated were 1,4-naphthoquinone (2.8%), 1,2-naphthoquinone (0.2%), 2-naphthol (6.3%), and trans-1,2-dihydroxy-1,2-dihydronaphthalene (5.3%). C. elegans oxidized both 1-naphthol and 1,4-naphthoquinone to 4-hydroxy-1-tetralone. The results suggest that C. elegans oxidizes naphthalene by a sequence of reactions similar to those reported for the mammalian metabolism of this hydrocarbon.
Chemical Phenomena↗
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↗
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↗
Synthesis and spectral properties of a hydrophobic fluorescent probe: 6-propionyl-2-(dimethylamino)naphthalene.
Environmentally sensitive fluorescent probes involve two groups, an electron donor and an electron acceptor, attached to an aromatic ring system, and maximal effects may be expected when these groups are as far apart as feasible. The syntheisis, characterization, and spectroscopic properties of 6-propionyl-2-(dimethylamino)naphthalene (PRODAN), a compound that fulfills these conditions, are described. The maximum of emission is at 401 nm in cyclohexane solution and at 531 nm in water solution, indicating an increase of dipole moment of approximately 20 D units on excitation to the lowest singlet state. The effect of temperature upon the spectral distribution and the bandwidth of fluorescence of PRODAN in 1:1 complexes with albumin shows the existence of a dynamic relaxation process of the protein surroundings within th 2-4 ns of the fluorescence lifetime.
2-Naphthylamine↗
Semisynthetic beta-lactam antibiotics. II Cephalosporin derivatives in the naphthalene series. Chemical and microbiological properties.
A seris of new 7-acylamidocephalosporins, containing a substituted naphthalene moiety in the side chain, has been prepared and tested for their in vitro antibacterial activity. Some observations are made on the structure-activity relationships.
Bacteria↗
[Synthesis and pharmacological activity of 1,2,3-triazole derivatives of naphthalene, quinoline and pyridine].
The preparation of three series of 1,2,3-triazol derivatives, with a naphthalene, quinoline or pyridine ring in 1 position, is described. Preliminary pharmacological screening of some of these compounds showed no appreciable activity.
Animals↗