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PubMed1983

Electron microscope heteroduplex mapping of naphthalene oxidation genes on the NAH7 and SAL1 plasmids.

Introduction of the transposon Tn5 to serve as a marker allows electron microscope heteroduplex mapping of the naphthalene oxidation genes on the approximately 83-kb NAH7 and the related approximately 85-kb SAL1 plasmids. The electron microscope-mapped gene positions on the NAH7 plasmid are in close agreement with those mapped previously by restriction digestion. The SAL1 plasmid can be considered as a mutant NAH7 plasmid which fails to direct the conversion of naphthalene to salicylate because of a mutational block but retains intact coding sequences for salicylate oxidation. Analysis of heteroduplex molecules formed between the SAL1 and NAH7::Tn5 EcoRI fragments and the known NAH7/SAL1 homology strongly suggest that the SAL1 DNA is completely homologous to NAH7 DNA except that a approximately 2.5-kb DNA segment constituting most of the nahA gene is replaced by approximately 4.6-kb nonhomologous DNA.

Chromosome Mapping↗
PubMed1980

Rapid analysis of naphthalene and its metabolites in biological systems: determination by high-performance liquid chromatography/fluorescence detection and by plasma desorption/chemical ionization mass spectrometry.

A rapid procedure for the determination of naphthalene and its metabolites in bile of rainbow trout and mice is described. The integrated analytical techniques combine high-performance liquid chromatography/ultraviolet fluorescence detection and plasma desorption/chemical ionization mass spectrometry for identification and quantitation. After separation by reverse-phase liquid chromatography, naphthalene and its metabolites are detected and quantitated by ultraviolet fluorescence spectrometry. Identification of two metabolites is confirmed by mass spectrometry. A direct insertion probe tip for a conventional chemical ionization mass spectrometer was modified to obtain spectra of thermally labile compounds. A spectrum of less than 100 ng of naphthyl glucuronide, a labile glucuronic acid conjugate of 1-naphthol, was obtained with this system.

Animals↗
PubMed1995

Prediction of denaturing tendency of organic solvents in mixtures with water by measurement of naphthalene solubility.

Addition of miscible organic solvents to water increases the solubility of naphthalene. The logarithm of the solubility is linearly dependent on the co-solvent concentration, in an intermediate range. The relative solubilising effects of different solvents correlate well with their known tendency to denature proteins (using literature data for trypsin, cytochrome c, chymotrypsinogen, chymotrypsin, laccase and myoglobin). This is expected if denaturation occurs when the hydrophobic effect has been reduced by a characteristic extent for a given protein. Naphthalene solubility predicts denaturation as well as does the denaturation capacity model.

Naphthalenes↗
PubMed1986

Teratologic evaluation of hexabrominated naphthalenes in C57BL/6N mice.

Hexabrominated naphthalenes (HBNs) have been identified as contaminants in the commercial PBB mixture, Firemaster. Similarities between polyhalogenated naphthalenes and polyhalogenated biphenyls, dibenzofurans, and dibenzo-p-dioxins with regards to structure and capacity to elicit certain toxicological responses in laboratory animals have previously been evaluated. In this study, teratogenicity and embryo/fetal toxicity, which have been associated with maternal exposure to other toxic polyhalogenated aromatics, was characterized for a synthetic mixture of HBNs in C57BL/6N mice. Pregnant adult mice were treated on gestation Days 6 through 15 with 0.5, 1.0, 2.5, 5.0, 7.5, and 10.0 mg HBN/kg body wt/day and sacrificed on gestation Day 18. Maternal toxicity as evidenced by decreased body weight gain or actual weight loss was observed at 7.5 and 10.0 mg/kg/day. Maternal liver-to-body weight ratios were increased relative to controls at all exposure levels. Dose-related increases were recorded in fetal mortality at 5.0, 7.5, and 10.0 mg/kg/day, and in the incidence of various teratogenic effects at all dose levels. Kidney lesions, best described as apparent hydronephrosis, were the most sensitive fetal abnormality observed, followed by a reduction in the size of lymphatic organs (thymus and spleen), cleft palate, subcutaneous edema, sternebral anomalies, and delayed cranial ossification. HBNs are concluded to be potent fetotoxic and teratogenic agents producing similar effects to TCDD and other toxic polyhalogenated aromatic hydrocarbons.

Animals↗
PubMed2004

Synthesis and biological characterization of novel hybrid 7-[[2-(4-phenyl-piperazin-1-yl)-ethyl]-propyl-amino]-5,6,7,8-tetrahydro-naphthalen-2-ol and their heterocyclic bioisosteric analogues for dopamine D2 and D3 receptors.

In a recent preliminary communication we described the development of a series of hybrid molecules for the dopamine D2 and D3 receptor subtypes. The design of these compounds was based on combining pharmacophoric elements of aminotetralin and piperazine molecular fragments derived from known dopamine receptor agonist and antagonist molecules. Molecules developed from this approach exhibited high affinity and selectivity for the D3 receptor as judged from preliminary [(3)H]spiperone binding data. In this report, we have expanded our previous finding by developing additional novel molecules and additionally evaluated functional activities of these novel molecules in the [(3)H]thymidine incorporation mitogenesis assay. The binding results indicated highest selectivity in the bioisosteric benzothiazole derivative N6-[2-(4-phenyl-piperazin-1-yl)-ethyl]-N6-propyl-4,5,6,7-tetrahydro-benzothiazole-2,6-diamine (14) for the D3 receptor whereas the racemic compound 7-([2-[4-(2,3-dichloro-phenyl)-piperazin-1-yl]-ethyl]-propyl-amino)-5,6,7,8-tetrahydro-naphthalen-2-ol (10c) showed the strongest potency. Mitogenesis studies to evaluate functional activity demonstrated potent agonist properties in these novel derivatives for both D2 and D3 receptors. In this regard, compound 7-[[4-(4-phenyl-piperazin-1-yl)-butyl]-prop-2-ynyl-amino]-5,6,7,8-tetrahydro-naphthalen-2-ol (7b) exhibited the most potent agonist activity at the D3 receptor, 10 times more potent than quinpirole and was also the most selective compound for the D3 receptor in this series. Racemic compound 10a was resolved; however, little separation of activity was found between the two enantiomers of 10a. The marginally more active enantiomer (-)-10a was examined in vivo using the 6-OH-DA induced unilaterally lesioned rat model to evaluate its activity in producing contralateral rotations. The results demonstrated that in comparison to the reference compound apomorphine, (-)-10a was quite potent in inducing contralateral rotations and exhibited longer duration of action.

Animals↗
PubMed2006

Dicationic DNA-targeted antiprotozoal agents: naphthalene replacement of benzimidazole.

A series of naphthalene analogues of highly active benzimidazole diamidines were synthesized using sequential Stille and Suzuki coupling reactions for preparation of the bis-nitrile intermediates. All of the diamidines showed strong DNA affinities as judged by high DeltaTm values with poly(dA-dT). The dicationic compounds were quite active in vitro versus Trypanosoma brucei rhodesiense (T. b. r.) exhibiting IC50 values ranging from 4 to 98 nM. These compounds were also active versus Plasmodium falciparum (P. f.) giving IC50 values ranging from 4 to 33 nM. Two of the compounds showed good activity in vivo in the STIB900 model for acute African trypanosomiasis; one gave 3/4 cures and the other gave 4/4 cures on ip dosage of 20 mg/kg for 4 days. The amidoxime prodrugs of the naphthalene analogues were essentially ineffective.

Animals↗
PubMed2004

1- and 2-substituted naphthalenes: a new class of potential hypotensive agents.

A series of 2-substituted aminomethyloxy naphthalenes 1 and 4-(1-naphthoxy-2-substituted aminomethyl)-butanoic acids 2 were synthesized by Mannich reaction of 4-(2-naphthoxy)-butanoic acid 3 and 4-(1-naphthoxy)-butanoic acid 4 with appropriate secondary amines and para-formaldehyde. The newly synthesized compounds were tested for their hypotensive activity at 5 mg/kg i.v. dose in cats. The results indicated that the analogue 2-(N4-phenyl-N1-piperazino)-methyloxy naphthalene 1d (> N = N4-phenyl-N1-piperazino) was the most active analogue when its hypotensive activity was compared to the reference compound propranolol.

Animals↗
PubMed2004

Privileged scaffolds for blocking protein-protein interactions: 1,4-disubstituted naphthalene antagonists of transcription factor complex HOX-PBX/DNA.

Structure-based-design studies, with the crystal structure of the HOXB1-PBX1/DNA transcription factor complex, were used to identify 1,4-disubstituted naphthalenes as potential antagonists. An initial library of 32 analogs was synthesized, two of which were found to be more potent than the reported activity for a 12 amino acid peptide antagonist. Antagonists were also identified of the related BRN1/DNA and BRN2/DNA transcription factor complexes indicating that a 1,4-disubstituted naphthalene may be a privileged scaffold for preparing screening libraries targeting this family of transcription factor complexes.

Crystallography, X-Ray↗
PubMed2006

4-[6-(2-Aminoethyl)naphthalen-2-yl]benzonitriles are potent histamine H3 receptor antagonists with high CNS penetration.

4-[6-(2-Tertiaryaminoethyl)naphthalen-2-yl]benzonitriles are conformationally constrained histamine H3 receptor antagonists with high potency and selectivity. The analogs were designed around a naphthalene core, with the goal of enhancing lipophilicity and CNS penetration, as compared to a previously reported benzofuran series. The SAR of the tertiary amine moiety is similar to that reported for the benzofuran series, with analogs bearing a 2-methylpyrrolidine substituent possessing the greatest rat and human H3 receptor binding affinities.

Animals↗
PubMed2006

Free radical scavenging activity of the marine mangrove Rhizophora apiculata bark extract with reference to naphthalene induced mitochondrial dysfunction.

Rhizophora apiculata bark extract was tested for its free radical scavenging activity and protective role against mitochondrial dysfunction in naphthalene stressed rats. Lipid peroxidation activity was increased and activity of mitochondrial enzymes (cytochrome-c-oxidase, NADH-dehydrogenase, alpha-ketoglutarate dehydrogenase and succinate dehydrogenase) and glutathione was decreased in the liver and kidney of rats intoxicated with naphthalene when compared to control rats. Intraperitoneal administration of plant extract significantly reduced the lipid peroxidation, increased the activity of mitochondrial enzymes and increased glutathione to near control levels. These results suggest that the sulfated polysaccharides in R. apiculata play a protective role through their free radical scavenging properties.

Animals↗
PubMed2005

Groundwater contamination by chlorinated naphthalenes and related substances caused by activities of a former military base.

Water samples derived from two different aquifer layers of six sampling sites were analysed by GC/MS in order to characterize a groundwater contamination caused by chemicals used for wood impregnation. Mono- and dichlorinated naphthalenes, chlorobenzo(b)thiophene, 1-chloro-4-naphthol, 1-chloronaphthoic acid, acenaphthene and methyled naphthalenes were identified as the main pollutants and quantified. 1-Chloro-4-naphthol and 1-chloronaphthoic acid are discussed as possible indicators for anaerobic degradation processes. Results of inorganic and compound specific stable carbon isotope analyses revealed only a minor degree of microbiological transformation. Thus, sorption was characterized as the main attenuation process within the aquifer affecting the contamination described.

Acenaphthenes↗
PubMed2007

Chlorinated naphthalene formation from the oxidation of dichlorophenols.

Polychlorinated naphthalenes (PCNs) formed along with dibenzo-p-dioxin and dibenzofuran products in the slow combustion of dichlorophenols (DCPs) at 600 degrees C were identified. Each DCP reactant produced a unique set of PCN products. Major PCN congeners observed in the experiments were consistent with products predicted from a mechanism involving an intermediate formed by ortho-ortho carbon coupling of phenoxy radicals; polychlorinated dibenzofurans (PCDFs) are formed from the same intermediate. Tautomerization of the intermediate and H2O elimination produces PCDFs; alternatively, CO elimination to form dihydrofulvalene and fusion produces naphthalenes. Only trace amounts of tetrachloronaphthalene congeners were formed, suggesting that the preferred PCN formation pathways from chlorinated phenols involve loss of chlorine. 3,4-DCP produced the largest yields of PCDF and PCN products with two or more chlorine substituents. 2,6-DCP did not produce tri- or tetra-chlorinated PCDF or PCN congeners. It did produce 1,8-DCN, however, which could not be explained.

Air Pollutants↗
PubMed2004

Polychlorinated naphthalenes in animal aquatic species and human exposure through the diet: a review.

Polychlorinated naphthalenes (PCNs) are a group of environmental pollutants, which contain one to eight chlorine atoms per naphthalene molecule, forming a total of 75 possible congeners. Several of the PCN congeners display toxicity similar to that of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) through AhR-mediated mechanisms. There are toxicological similarities between PCNs and other well known environmental contaminants such as polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs). However, in contrast to these compounds, information on exposure to PCNs for non-occupationally exposed populations is rather scarce. In this article, information on human exposure to PCNs through dietary intake is reviewed. Because this information is very limited and taking into account that most data on PCN levels in potential foods concern to aquatic species, these data are also reviewed. It is concluded that further investigations on dietary intake and potential human health effects of PCNs are clearly necessary.

Animals↗
PubMed2005

Avoidance of low doses of naphthalene by Collembola.

The introduction of behavioural aspects of soil animals in ecological risk assessment would allow us to better assess soil quality, all the more if a range of animal populations are considered. We compared the avoidance behaviour of several strains of springtails (Arthropoda: Collembola) obtained from different soils. Naphthalene, a polycyclic aromatic hydrocarbon (PAH), widely represented in soils polluted with hydrocarbons, was tested in aqueous solutions on nine springtail species issuing from four sites. Fine quartz sand saturated with an aqueous solution of naphthalene was avoided by most of the tested species, avoidance being, however, detected down to a concentration of 0.030 mg L(-1). Folsomia candida (Isotomidae) was shown to be relatively tolerant to pollutants compared to other Collembola such as Mesaphorura macrochaeta, Mesaphorura yosii (Onychiuridae), Parisotoma notabilis (Isotomidae) and Arrhopalites caecus (Arrhopalitidae). Differences between strains could not be explained by properties of the original soils.

Animals↗
PubMed2004

Complete sequence and genetic organization of pDTG1, the 83 kilobase naphthalene degradation plasmid from Pseudomonas putida strain NCIB 9816-4.

The complete 83,042 bp sequence of the circular naphthalene degradation plasmid pDTG1 from Pseudomonas putida strain NCIB 9816-4 was determined in order to examine the process by which the nah and sal operons may have been compiled and distributed in nature. Eighty-nine open reading frames were predicted using computer analyses, comprising 80.0% of the pDTG1 DNA sequence. The most distinctive feature of the plasmid is the upper and lower naphthalene degradation operons, which occupy 9.5 kb and 13.4 kb regions, respectively, bordered by numerous defective mobile genetic element fragments. Identified on this plasmid were homologues of genes required for large plasmid replication, maintenance, and conjugation, as well as transposases, resolvases, and integrases, suggesting an evolution that involved the lateral transfer of DNA between bacterial species. Also found were genes that contain a high degree of sequence similarity to other known degradation genes, as well as genes involved in chemotaxis. Although the incompatibility group designation of pDTG1 remains unresolved, striking sequence organization and homology exists between the plasmid backbones of pDTG1 and the IncP-9 toluene-degradation plasmid pWW0, which suggests a divergent evolution from a progenitor plasmid prior to degradative gene incorporation.

Catalytic Domain↗
PubMed2005

Overexpression, purification and characterization of a new salicylate hydroxylase from naphthalene-degrading Pseudomonas sp. strain ND6.

A new salicylate hydroxylase from naphthalene-degrading Pseudomonas sp. strain ND6, NahU, has been identified. The nahU is an isofunctional gene of the classic salicylate hydroxylase gene, nahG, and situated outside the transcriptional unit forming the naphthalene degradation lower pathway. Both genes, nahU and nahG of Pseudomonas sp. ND6, have been cloned and overexpressed in Escherichia coli BL21 (DE3). NahU contains 429 amino acid residues and NahG contains 434 amino acid residues. SDS-PAGE analysis showed that both NahG and NahU are about 47 kDa. Both enzymes exhibit broad substrate specificities and metabolize salicylate, sulfosalicylate, aspirin, methylsalicylate, chlorosalicylate and 3,5-dinitrosalicylate. The comparison of the Km and Vmax values for NahG and NahU demonstrated that NahU possesses a higher binding ability to salicylate and cofactors and catalytic efficiency.

Bacterial Proteins↗
PubMed2006

Antiprotozoal and cytotoxic naphthalene derivatives from Diospyros assimilis.

Chemical investigation of the roots of Diospyros assimilis had led to the isolation and characterization of six naphthalene derivatives, two 2-naphthaldehyes, namely 4-hydroxy-3,5-dimethoxy-2-naphthaldehyde 1, 4-hydroxy-5-methoxy-2-naphthaldehye 2, its related isomer 5-hydroxy-4-methoxy-2-naphthaldehyde 3 and three commonly occurring naphthoquinones, diospyrin 4, 8'-hydroxyisodiospyrin 5 and the simple monomer, plumbagin 6. Their chemical structures were established by detailed NMR investigations including 1H and 13C NMR, HSQC, HMBC and NOESY experiments. In addition, the naphthalene derivatives 1-5 were evaluated for their in vitro antiprotozoal activity against protozoan parasites belonging to the genera Trypanosoma, Leishmania and Plasmodium. Among the tested compounds, naphthaldehyde 1 showed moderate inhibition of the growth of the parasites, T. brucei, T. cruzi, L. donovani with IC50 values of 19.82, 12.28 and 38.78 microM and displayed cytotoxicity towards rat skeletal myoblasts (L-6 cells) with IC50 of 174.94 microM, while 2 and 3 were found to be comparatively less active to 1. The dimeric quinones 4 and 5 exhibited good activity against T. brucei and L. donovani with IC50 of 1.12 and 8.82 microM and 12.94 and 16.66 microM respectively.

Aldehydes↗
PubMed2002

Identification and quantification of polar naphthalene derivatives in contaminated groundwater of a former gas plant site by liquid chromatography-electrospray ionization tandem mass spectrometry.

A liquid chromatography (LC) method followed by electrospray ionization (ESI) and tandem mass spectrometry (MS-MS) was developed for the quantification of acidic naphthalene derivatives in the concentration range 0.1 to 100 microg/l without excessive sample preparation. For optimal sensitivity the LC-MS-MS measurements were performed recording mass fragmentation by collision induced dissociation in the multiple reaction mode. The collision energy was optimized for every analyte. The matrix effects of the sample were investigated by spiking standards of 1-naphthoic acid with humic acid (HA) and with calcium chloride. While HA decreased the signal intensity an increase was observed in the presence of calcium chloride. For the investigated groundwater samples of a tar oil contaminated site a complete separation of the analytes from the sample matrix by reversed-phase separation could be obtained. The absence of matrix effects on quantification results was confirmed by comparison of results based on external calibration with those based on standard addition of the analytes to a groundwater sample. In four groundwater samples of the contaminated site naphthalene derivatives like 1-naphthoic acid, 2-naphthoic acid, 1-naphthylacetic acid, 2-naphthylacetic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-3-naphthoic acid, and naphthyl-2-methylenesuccinic acid have been detected.

Chromatography, Liquid↗