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PubMed1978

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↗
PubMed1978

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↗
PubMed1995

Degradation of naphthalene by a Pseudomonas strain NGK1.

A Pseudomonas strain NGK1 capable of degrading naphthalene as a sole carbon source was isolated from biological waste treatment effluent. After 48 hr of incubation in 0.1% naphthalene mineral salts medium, the bacterial culture showed irregular clumped cells and salicylic acid (68 micrograms per ml) in the medium (pH 3.8). The strain degraded naphthalene through salicylate and catechol as was evidenced by metabolite characterization, oxygen uptake and enzymatic studies.

Naphthalenes↗
PubMed1994

Subretinal neovascularization after naphthalene damage to the rabbit retina.

PURPOSE: To examine the retinotoxic effect of naphthalene, a powerful oxidative agent and a well-known cataractogenic agent. METHODS: A 10% solution of naphthalene dissolved in paraffin oil was given every other day by gavage to 31 pigmented rabbits for 5 weeks, at a dose of 1 g/kg body weight. Four rabbits who received only paraffin oil served as controls. The eyes were clinically followed up by means of ophthalmoscopy and retinal fluorangiography. At selected intervals, the eyes were examined with light microscopy and transmission electron microscopy. RESULTS: The first lesions were focal and appeared in the periphery of the fundus about 3 weeks after the beginning of treatment and tended to spread over the entire retina. Histologically, there was a degeneration of photoreceptors, accompanied by a reaction and proliferation of retinal pigment epithelium (RPE) that phagocytized the damaged visual cells. After about 3 months, the proliferation of RPE was followed by subretinal neovascularization (SRN). Both mature fenestrated and thick-walled non-fenestrated capillaries penetrated Bruch's membrane, enveloped by abundant fibrous extracellular matrix and accompanied by pericytes. As a consequence of this process, the retina was focally transformed into a "neovascular complex" in which a vascular plexus was intermingled with pseudo-acinar cavities lined by RPE. There were no signs of SRN at retinal fluorangiography, possibly because of the dense microenvironment of extracellular matrix and RPE cells of the neovascular complexes. CONCLUSIONS: Naphthalene degeneration of the rabbit retina appears to be a simple model of photoreceptor vulnerability in the first stages of SRN thereafter. The close chronologic and topographic relationship between the appearance of the anomalous vessels and RPE alteration and the close resemblance with previous models of experimental SRN may support the hypothesis of an experimental model of SRN triggered by the RPE.

Animals↗
PubMed1997

[Genetic control of naphthalene biodegradation by a strain of Pseudomonas sp. 8909N].

The ability of Pseudomonas sp. 8909N to grow using Naphthalene and salicylate as the sole source of carbon and energy is mediated by the presence of an 80-kb conjugative pBS1145 plasmid in this strain. Structural genes for naphthalene degradation in pBS1145 plasmid are homologous to those in the known NAH7 plasmid. Conjugational transfer of pBS1145 from the original strain is accompanied by a deletion of a plasmid DNA fragment that does not affect the Nah+Sal+ phenotype. Plasmid pBS1145 specifies a low constitutive level of catechol-2,3-dioxygenase, the key enzyme of the metha-pathway of catechol degradation. Activity of this enzyme is induced in the presence of salicylate. Enzymes of both the metha and ortho-pathway of catechol degradation (catechol-2-3-dioxygenase) were shown to operate in the process of naphthalene degradation in Pseudomonas sp. 8909N. The ability of this strain to bring about transformation of polycyclic aromatic hydrocarbon phenanthrene is also controlled by pBS1145 plasmid.

Biodegradation, Environmental↗
PubMed2000

Conformational study by CD of chirally tethered naphthalene moieties: toward an understanding of the asymmetric intramolecular coupling reaction?

The carbonate (R,R)-1 and the diester (R,R)-2, precursors of optically active 1,1'-binaphthyl derivatives through asymmetric intramolecular coupling, were prepared and fully characterized. The absorption and CD spectra, together with the cholesteric induction measurement of (R,R)-1, indicate that it assumes a conformation in which the naphthalene rings are M-skewed. Since the intramolecular coupling of (R,R)-1 affords a P-twisted (S) binaphthyl derivative, a change of twist from M to P must occur during the reaction. Moreover, this conformation allows the coupling to occur along only one pathway, thus explaining the high stereoselectivity. The CD analysis of (R,R)-2 indicates that it assumes a rigid conformation as well, with the naphthalene rings fixed relative to each other. However, in this compound the naphthalene moieties can give rise to a coupling reaction following two different pathways, leading to oppositely configured binaphthyls with almost the same probability so that low stereoselectivity results. Copyright 2000 Wiley-Liss, Inc.

Journal Article↗
PubMed2003

Naphthalene-1,8-diyl bis(halogenophosphanes): novel syntheses and structures of useful synthetic building blocks.

A series of new bay region disphospha-functionalised naphthalenes is reported. The reduction of ylidic phosphonium phosphoride NapP(2)Cl(6) (1) (Nap=naphthalene-1,8-diyl) with MeOPCl(2) gives the important synthon Nap(PCl(2))(2) (2) in nearly quantitative yield. Reaction of 1 with magnesium metal affords (NapP(2))(n) (3), which reacts with Br(2) and I(2), yielding Nap(PBr(2))(2) (4) and Nap(PI)(2) (5), respectively. X-ray structure determinations reveal a twisted geometry of the naphthalene ring in sterically strained 2 and 4, whilst the presence of a P-P bond in 5 results in the release of the steric strain and generation of the planar NapP(2) moiety. Although the tetrahedral P environments are severely distorted the sigma(3)P-sigma(3)P bonding in 5 represents a new type of P-P bonding environment in 1,8-diphosphanaphthalenes. Compounds 1, 4 and 5 each represent the highest coordination, achievable by direct halogenation. The new compounds 2-5 were fully characterised by NMR, IR, and Raman spectroscopy, mass spectrometry, and elemental analysis.

Journal Article↗
PubMed2001

Determination of the electron affinities of alpha- and beta-naphthyl radicals using the kinetic method with full entropy analysis. The C-H bond dissociation energies of naphthalene.

The C - H bond dissociation energies for naphthalene were determined using a negative ion thermochemical cycle involving the gas-phase acidity (Delta H (acid)) and electron affinity (EA) for both the alpha- and beta-positions. The gas-phase acidity of the naphthalene alpha- and beta-positions and the EAs of the alpha- and beta-naphthyl radicals were measured in the gas phase in a flowing after glow-triple quadrupole apparatus. A variation of the Cooks kinetic method was used to measure the EAs of the naphthyl radicals by collision-induced dissociation of the corresponding alpha- and beta-naphthylsulfinate adducts formed by reactions in the flow tube portion of the instrument. Calibration references included both pi and sigma radicals, and full entropy analysis was performed over a series of calibration curves measured at collision energies ranging from 3.5 to 8 eV (center-of-mass). The measured EAs are 33.0 +/- 1.4 and 31.4 +/- 1.0 kcal mol(-1) (1 kcal = 4.184 kJ) for the alpha- and beta-naphthyl radicals, respectively. The gas-phase acidities for naphthalene were measured by the DePuy silane cleavage method, which utilizes the relative abundances of aryldimethylsiloxides and trimethylsiloxide that result from competitive cleavages from a proposed penta coordinate hydroxysiliconate intermediate. The measured acidities are 394.0 +/- 5.0 and 397.6 +/- 4.8 kcal mol(-1) for the alpha- and beta- positions, respectively. The C - H bond dissociation energies calculated from the thermochemical cycle are 113.4 +/- 5.2 and 115.4 +/- 4.9 kcal mol(-1) for the alpha- and beta-positions, respectively. These energies are, to within experimental error, indistinguishable and are approximately the same as the first bond dissociation energy for benzene.

Journal Article↗
PubMed1997

Heterogeneous Nucleation of Naphthalene Vapor on Water Surface

The evaporation of a water drop into a ternary gaseous mixture of air, steam, and naphthalene vapor was investigated. The experimental results were compared with a theoretical prediction based on a numerical solution of coupled boundary layer equations for heat and mass transfer from a drop moving in ternary gas. In the experiments the naphthalene vapor condensed on the water drop as a supercooled liquid even at temperatures far below the melting point of naphthalene. The condensation on drop surface is discussed in terms of classical theory of heterogeneous nucleation on smooth surfaces.

Journal Article↗
PubMed2002

Diversity of 16S rDNA and naphthalene dioxygenase genes from coal-tar-waste-contaminated aquifer waters.

Microbial diversity in four wells along a groundwater flowpath in a coal-tar-waste-contaminated aquifer was examined using RFLP analysis of both 16S rDNA and naphthalene dioxygenase (NDO) genes. Amplified ribosomal DNA restriction analysis (ARDRA) relied upon eubacteria-specific primers to generate four clone libraries. From each library, 100 clones were randomly picked for analysis. Sixty percent of 400 clones contained unique ARDRA patterns. Diversity indices calculated for each community were high (Shannon-Weaver, H = 3.53 to 3.69). Clones representing ARDRA patterns found in the highest abundance were sequenced (31 total). Sequences related to aerobic bacteria (e.g., Nitrospira, Methylomonas, and Gallionella) predominated among those retrieved from the uncontaminated area of the site, whereas sequences related to facultatively aerobic and anaerobic bacteria (e.g. Azoarcus, Syntrophus, and Desulfotomaculum) predominated among those retrieved from contaminated areas of the site. Using NDO-specific primers and low-stringency PCR conditions, variability in RFLP patterns was only detected in community-derived DNA (3 of 4 wells) and not in 5 newly isolated naphthalene-degrading pure cultures. The ARDRA patterns of the pure culture isolates were not found in the clone libraries. Polymorphisms in community 16S rDNA and NDO genes found in well-water microorganisms reflected distinctive geochemical conditions across the site. Sequences related to sulfate-reducing bacteria were found in groundwater that contained sulfide, while sequences related to Gallionella, Syntrophus, and nitrate-reducing aromatic hydrocarbon-degrading bacteria were found in groundwater that contained ferrous iron, methane, and naphthalene, respectively.

Bacteria, Aerobic↗
PubMed2004

A theoretical study of the cis-dihydroxylation mechanism in naphthalene 1,2-dioxygenase.

The catalytic mechanism of naphthalene 1,2-dioxygenase has been investigated by means of hybrid density functional theory. This Rieske-type enzyme, which contains an active site hosting a mononuclear non-heme iron(II) complex, uses dioxygen and two electrons provided by NADH to carry out the cis-dihydroxylation of naphthalene. Since a (hydro)peroxo-iron(III) moiety has been proposed to be involved in the catalytic cycle, it was probed whether and how this species is capable of cis-dihydroxylation of the aromatic substrate. Different oxidation and protonation states of the Fe-O2 complex were studied on the basis of the crystal structure of the enzyme with oxygen bound side-on to iron. It was found that feasible reaction pathways require a protonated peroxo ligand, FeIII-OOH; the deprotonated species, the peroxo-iron(III) complex, was found to be inert toward naphthalene. Among the different chemical patterns which have been explored, the most accessible one involves an epoxide intermediate, which may subsequently evolve toward an arene cation, and finally to the cis-diol. The possibility that an iron(V)-oxo species is formed prior to substrate hydroxylation was also examined, but found to implicate a rather high energy barrier. In contrast, a reasonably low barrier might lead to a high-valent iron-oxo species [i.e. iron(IV)-oxo] if a second external electron is supplied to the mononuclear iron center before dioxygenation.

Bacterial Proteins↗
PubMed2006

Degradation of phenanthrene by Burkholderia sp. C3: initial 1,2- and 3,4-dioxygenation and meta- and ortho-cleavage of naphthalene-1,2-diol.

Burkholderia sp. C3 was isolated from a polycyclic aromatic hydrocarbon (PAH)-contaminated site in Hilo, Hawaii, USA, and studied for its degradation of phenanthrene as a sole carbon source. The initial 3,4-C dioxygenation was faster than 1,2-C dioxygenation in the first 3-day culture. However, 1-hydroxy-2-naphthoic acid derived from 3,4-C dioxygenation degraded much slower than 2-hydroxy-1-naphthoic acid derived from 1,2-C dioxygenation. Slow degradation of 1-hydroxy-2-naphthoic acid relative to 2-hydroxy-1-naphthoic acid may trigger 1,2-C dioxygenation faster after 3 days of culture. High concentrations of 5,6- and 7,8-benzocoumarins indicated that meta-cleavage was the major degradation mechanism of phenanthrene-1,2- and -3,4-diols. Separate cultures with 2-hydroxy-1-naphthoic acid and 1-hydroxy-2-naphthoic acid showed that the degradation rate of the former to naphthalene-1,2-diol was much faster than that of the latter. The two upper metabolic pathways of phenanthrene are converged into naphthalene-1,2-diol that is further metabolized to 2-carboxycinnamic acid and 2-hydroxybenzalpyruvic acid by ortho- and meta-cleavages, respectively. Transformation of naphthalene-1,2-diol to 2-carboxycinnamic acid by this strain represents the first observation of ortho-cleavage of two rings-PAH-diols by a Gram-negative species.

Biodegradation, Environmental↗
PubMed1976

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↗
PubMed2004

Molecularly imprinted solid-phase extraction of naphthalene sulfonates from water.

A new polymeric sorbent synthesised by exploiting molecular imprinting technology has been used to selectively extract naphthalene sulfonates (NSs) directly from aqueous samples. In the non-covalent molecular imprinting approach used to prepare this polymer, 1-naphthalene sulfonic acid (1-NS) and 4-vinylpyridine (4-VP) were used as a template molecule and functional monomer, respectively, and both dissolved in a mixture of methanol/water (4:1) as porogen together with the cross-linker ethylene glycol dimethacrylate. The new non-covalent molecularly imprinted polymer (MIP) prepared in aqueous environment was used as a sorbent in solid-phase extraction (SPE) to selectively extract a group of naphthalene mono- and disulfonates. When one litre of a standard aqueous solution, which contained a mixture of eight NSs, was percolated through the SPE cartridge, all the NSs were retained on the MIP because of the cross-reactivity of the polymer. Recoveries were higher than 80% for all the compounds even after a clean-up step with methanol (MeOH). The MIP was also used to analyse water from the Ebro river.

Naphthalenesulfonates↗
PubMed2002

Detection in coal tar waste-contaminated groundwater of mRNA transcripts related to naphthalene dioxygenase by fluorescent in situ hybridization with tyramide signal amplification.

The ideal ecological metabolic activity assay would be applied to naturally occurring microbial populations immediately fixed in the field, and the assay would focus upon intracellular parameters indicative of a dynamic biogeochemical process. In this study, fluorescent in situ hybridization (FISH) with tyramide signal amplification (TSA) detected intracellular mRNA in bacteria. Detection sensitivity was enhanced by using a Hamamatsu color chilled CCD camera and extended exposure times. Pseudomonas putida NCIB 9816-4, a model naphthalene degrading bacterium, was used to refine the protocol. Probe Ac627BR was developed for detecting naphthalene dioxygenase (nahAc) mRNA transcripts. Only induced cells showed positive hybridization to probe Ac627BR. Results were verified by RNase A or DNase I digestion of samples prior to hybridization. When applied to field-fixed groundwater samples, the naphthalene dioxygenase mRNA probe conferred fluorescence on a subset (approximately 1%) of the cells present in the contaminated groundwater. This methodology represents progress towards achieving one of the longstanding goals of environmental microbiology: to simultaneously ascertain the identity, activity, and biogeochemical impact of individual microorganisms in situ-in soil, water, or sediment where they dwell.

Bacteria↗
PubMed1999

Nucleotide sequences and characterization of genes encoding naphthalene upper pathway of pseudomonas aeruginosa PaK1 and Pseudomonas putida OUS82.

A 12,808-nucleotide containing DNA fragment cloned from naphthalene-utilizing (Nah+) Pseudomonas aeruginosa PaK1 was analyzed and compared with the genes (pah(OUS)) of a 14,462-nucleotide DNA fragment from Pseudomonas putida OUS82. The DNA sequence analyses demonstrated that the naphthalene upper-pathway genes and their deduced enzymes were very similar between the two bacteria: nucleotide similarities, 83-93%; amino acid similarities, 79-95%. These genes were also similar to those of the nah operon of plasmid NAH7; in particular, the OUS82 genes were similar to the nah genes, whereas the PaK1 genes were almost identical to the dox genes of Pseudomonas sp. C18. A region homologous with the 84-bp repeated sequence that Eaton (J. Bacteriol., 176, 7757-7762, 1994) has found at a site upstream of he nah operon was found only in a region downstream of the pah(PaK) gene cluster in PaK1 and on both sides of the pah(OUS) gene cluster in OUS82. A PaK1 gene, corresponding to an unknown gene (nahQ) in the nah operon, is located between the 1,2-dihydroxynaphthalene dioxygenase gene and the trans-o-hydroxybenzylindenepyruvate (tHBP A) hydratase-aldolase gene (nahE), and was suggested to be involved in the conversion of naphthalene to salicylate. Just downstream of the pah(PaK) gene cluster, a portion of a region was identical to one-third of the transposase gene (tnpA) in a phenol-catabolic plasmid pEST1226.

Journal Article↗
PubMed2001

Combinatorial screening of heterogeneous catalysis in selective oxidation of naphthalene by laser-induced fluorescence imaging.

Heterogeneous catalysis is one of the most important processes in the petroleum and the chemical industries. To be able to screen catalysts at high throughput will dramatically improve performance and reduce costs. Here we used laser-induced fluorescence imaging as a high-throughput screening technique in the combinatorial discovery of active catalysts for naphthalene oxidation. Binary catalysts of V-Mo-O, V-Sn-O, V-Ti-O, and V-W-O in various 15-member libraries were screened. Laser ablation ICPMS was employed to confirm the composition of the individual catalysts in the combinatorial library. The addition of MoO3, WO3, SnO2, and TiO2 to V2O5 did not improve the catalytic activity in the conversion of naphthalene to naphthoquinone, but the overall activity was found to increase for certain binary samples. The screening of ternary catalysts of V-Sn-Mo-O revealed that the combination of V (45%)-Sn (45%)-Mo (10%) gave 70% higher catalytic activity than pure V2O5 in converting naphthalene to naphthoquinone. Reaction temperature and sample preparation effects on the activity and selectivity of catalysts are also studied in a combinatorial manner.

Journal Article↗
PubMed2005

Bis(cyclopentadienyl)titanium complexes of naphthalene-1,8-dithiolates, biphenyl 2,2'-dithiolates, and related ligands.

Titanocene 1,8-dithiolato-naphthalene and titanocene 2,2'-dithiolato biphenyl are produced by the reaction of naphtho[1,8-cd]-1,2-dithiole [or the biphenyl] with titanocene dicarbonyl (Ti(II)) in toluene at room temperature. The pro-ligands 2,7-di(tert-butyl)naphtho[1,8-cd]-1,2-dithiole, 5,6-dihydroacenaphtho[5,6-cd]-1,2-dithiole, 4,5-dithioacephenanthrylene, and 13,14-dithiapicene have been used in similar reactions with titanocene dicarbonyl to investigate the effect of steric bulk and of varying the naphthalene backbone on the final complex. The resulting Cp(2)TiS(2)Ar complexes (Ar = naphthalene) have been shown by temperature-dependent (1)H NMR spectroscopy to exist in solution in an envelope conformation with the six-membered TiS(2)C(3) rings undergoing inversion on the NMR time scale while the similar Cp(2)TiS(2)Ar complexes (Ar = biphenyl, binaphthalene) interconvert more rapidly. Titanocene 2,2'-disulfinato biphenyl has been synthesized by the salt elimination reaction of titanocene dichloride (Ti(IV)) and the disodium salt of biphenyl 2,2'-disulfinic acid. Finally, the effect of using pro-ligands where the sulfur atoms have been mono- or di-oxidized has been studied, and an interesting oxygen elimination reaction is observed for the S=O fragments but not for the SO(2) groups. All complexes have been characterized spectroscopically and seven X-ray structures are reported.

Journal Article↗