Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “NAPHTHALENES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25Linked to original sources
PubMed2003

Optimization of the biodegradation of naphthalene by a microorganism isolated from petroleum contaminated soil.

Response surface methodology (RSM) was used to optimise the process parameters to obtain maximum biodegradation of naphthalene. The factorial design employed, a face-centred cube, helped in identifying the combined best parameter conditions. Naphthalene-containing medium was inoculated with Pseudomonas fluorescens and incubated at different levels of agitation, pH, and temperature, and analyzed by Gas Chromatography-Mass Spectroscopy. As a result of the optimisation process, the process parameters found for maximum degradation of naphthalene by P. fluorescens were an agitation speed of 186 rpm, a pH of 7.3, and a temperature of 22.8 degrees C.

Biodegradation, Environmental↗
PubMedDate not supplied

[Formation of structured communities by natural and transgenic naphthalene-consuming bacteria].

This study concerns the formation of structured communities by pure cultures and binary associations of Pseudomonasfluorescens transgenic strains and natural heterotrophic bacterial species in naphthalene-containing media with various osmotic pressures. It was shown that cells of P. fluorescens strain 5RL, harboring a recombinant construct in the chromosome, were more resistant to the combined action of the stress factors under study than P. fluorescens 82/pUTK21, harboring a recombinant construct within a plasmid. Natural P. fluorescens 1 strains, particularly Vibrio sp. 14, were more viable at high osmotic pressures and naphthalene concentrations. Experiments with the combined introduction of transgenic and natural bacterial strains at high osmotic pressures demonstrated the stable coexistence of bacterial associations in biofilms, independent of naphthalene concentration. Strains considered for introduction into the environment for bioremediation should be assessed with regard to their susceptibility to the combined effect of anthropogenic and natural stress factors. The design of bacterial associations for the same purpose should take into account the effect of factors important for their survival in polluted areas.

Biodegradation, Environmental↗
PubMedDate not supplied

[Characteristics of natural strains of naphthalene-utilizing bacteria of the genus Pseudomonas].

Sixty-three strains of bacteria capable of utilizing naphthalene as the sole source of carbon and energy were isolated from 137 samples of soil taken in different sites in Belarus. All isolated bacteria contained extrachromosomal genetic elements of 45 to 150 kb in length. It was found that bacteria of 31 strains contained the IncP-9 incompatibility group plasmids, bacteria of one strain carried a plasmid containing replicons IncP-9 and IncP-7, and bacteria of 31 strains contained unidentified plasmids. Primary identification showed that the hosts of plasmids of naphthalene biodegradation are fluorescent bacteria of the genus Pseudomonas (P. putida and P. aeruginosa; a total of 47 strains) and unidentified nonfluorescent microorganisms (a total of 16 strains). In addition to the ability to utilize naphthalene, some strains exhibited the ability to stimulate the growth and development of the root system of Secale cereale.

Biodegradation, Environmental↗
PubMedDate not supplied

[Incompatibility group P-7 plasmids responsible for biodegradation of naphthalene and salicylate in fluorescent pseudomonads].

Analysis of seven plasmids (77 to 135 kbp in size) of the P-7 incompatibility group that are responsible for the biodegradation of naphthalene and salicylate has shown that the main natural host of IncP-7 plasmids is the species Pseudomonas fluorescens. The IncP-7 plasmids are structurally diverse and do not form groups, as is evident from their cluster analysis. The naphthalene catabolism genes of six of the IncP-7 plasmids are conservative and homologous to the catabolic genes of NAH7 and pDTG1 plasmids. The pAK5 plasmid contains the classical nahA gene, which codes for naphthalene dioxygenase, and the salicylate 5-hydroxylase gene (nagG) sequence, which makes the conversion of salicylate to gentisate possible.

Biodegradation, Environmental↗
PubMed2005

Whole cell-derived fatty acid profiles of Pseudomonas sp. JS150 during naphthalene degradation.

Changes in cellular fatty acid composition during naphthalene degradation, at the concentrations of 0.5 g l(-1) or 1.0 g l(-1), by Pseudomonas sp. JS150 were investigated. In response to naphthalene exposure an increase in saturated/unsaturated ratio was observed. Additionally, the dynamic changes involved alterations in the contents of hydroxy, cyclopropane and branched fatty acids. Among the classes of fatty acids tested the most noticeable changes in the abundance of cyclopropane fatty acids were observed. Since day 4 of incubation these fatty acids were not dectected in bacterial cells growing on naphthalene. In contrast, markedly increased in the percentage of hydroxy fatty acids over time was observed. However, the proportions of saturated straight-chain and branched fatty acids did not change such significantly.

Bacteriological Techniques↗
PubMedDate not supplied

[The construction and monitoring of genetically marked, plasmid-containing, naphthalene-degrading strains in soil].

A genetically marked, plasmid-containing, naphthalene-degrading strain, Pseudomonas putida KT2442(pNF142::TnMod-OTc), has been constructed. The presence of the gfp gene (which codes for green fluorescent protein) and the kanamycin and rifampicin resistance genes in the chromosome of this strain allows the strain's fate in model soil systems to be monitored, whereas a minitransposon, built in naphthalene biodegradation plasmid pNF142, contains the tetracycline resistance gene and makes it possible to follow the horizontal transfer of this plasmid between various bacteria. Plasmid pNF142::TnMod-OTc is stable in strain P. putida KT2442 under nonselective conditions. The maximal specific growth rate of this strain on naphthalene was found to be higher than that of the natural host of plasmid pNF142. When introduced into a model soil system, the genetically marked strain is stable and competitive for 40 days. The transfer of marked plasmid pNF142::TnMod-OTc to natural soil bacteria, predominantly fluorescent pseudomonads, has been detected.

Biodegradation, Environmental↗
PubMed1991

Regional enzyme profiles in rabbit lenses with early stages of naphthalene cataract.

The naphthalene cataract in the pigmented rabbit, in contrast to the corresponding model in the pigmented rat, is characterized by a rather unstable cataract development during the later stages. Some animals rapidly develop mature cataracts, others develop cortical cataracts with almost no further progression inspite of a continued naphthalene treatment. To get more insight into this phenomenon, a study with pigmented rabbits (8 weeks old) was designed and at different stages of cataract development lenses were separated in single layers with the Bonn freeze-sectioning device. The key enzymes of the carbohydrate metabolism and the redox potential were determined in those layers. The results of the biochemistry failed however to explain the prominent differences of cataract development in-vivo. We conclude from these findings that the naphthalene cataract model in the pigmented rabbit shall no longer be used in drug side-effect or efficacy studies.

Animals↗
PubMed1989

[Study on biosynthesis of indigo involving transferring naphthalene plasmid DNA from Pseudomonas to E. coli].

Indigo is one of the brilliant blue dyes, which was used to be extracted from plants, but now synthesized chemically. Indigo is also produced by bacteria. In recent years, Ensley, B. D. (1983) and Mermod, N. (1986) reported a pathway producing indigo of bacteria. We are currently studying indigo formation by bacteria. Using Pseudomonas sp. S13 harboring naphthalene degradation plasmid as donor and E. coli as recipient, conjugates and transformants with the plasmid were obtained. The conjugates and transformants were not only able to grow in medium with naphthalene as the sole carbon and energy source, but also to synthesize indigo in Lennox medium. The conjugates and transformants were grown in Lennox medium at 30 degrees C for 48 hr then resulted in synthesis of indigo. The production of indigo is increased in the presence of tryptophan or indole. Indigo formation was enhanced if the bacteria was grown in a medium supplemented with either 0.1% of naphthalene or 1% of salicylic acid. The present work opens a field for the synthesis of dyes by microbes and it might shed light on the potential use in controlling environmental pollution by engineering bacteria.

Coloring Agents↗
PubMed1989

Polybrominated naphthalene and diiodobenzene interactions with specific binding sites for 2,3,7,8-tetrachlorodibenzo-p-dioxin in rat liver cytosol.

We provide evidence for two new classes of halogenated aromatic hydrocarbon ligands for the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or Ah) receptor: brominated naphthalenes and iodobenzenes. Polybrominated naphthalenes with four or more bromine atoms concentrated in lateral positions were shown to bind specifically and with high affinity (Kd approximately 10(-8) M) to the Ah receptor in rat liver cytosol preparations. The hexabrominated naphthalene isomers bind with high and nearly equal affinities but have been previously shown to have different toxicological properties. Possible explanations for these differences include differences in metabolism, antagonist versus agonist Ah receptor binding of some isomers, and the involvement of other binding sites in vivo that require different structural requirements. The moderate binding activity of the diiodobenzenes suggests that thyroid hormones should receive further study as possible endogenous ligands for the Ah receptor. It is difficult to explain the binding results with these two classes of compounds using previously developed molecular concepts for Ah receptor interactions based primarily on molecular size considerations.

Animals↗
PubMed1989

[Cloning of Pseudomonas putida genes responsible for the primary stages of oxidation of naphthalene in Escherichia coli cells].

Data on cloning Pseudomonas putida D-plasmid pBS286 (IncP-9) genes which are responsible for primary stages of naphthalene oxidation as well as data on the expression of these genes in Escherichia coli cells are presented. Recombinant plasmid pBS959 containing the whole constitutive nahA locus encoding naphthalene dioxygenase, a key enzyme of the naphthalene oxidation pathway, has been constructed on the basis of the pUC19 vector. An evidence has been obtained that at least a portion of the sequence of structural nahB gene is cloned in the recombinant pBS959 plasmid. Constitutive expression of the nahA gene is controlled by its own promoter and leads to conversion of indole to indigo in E. coli cells, strain HB101. Plasmid pBS959 is characterized by high structural stability; some instability observed is due to segregation.

Chromosome Mapping↗
PubMedDate not supplied

[Mutants of the plasmid for biodegradation of naphthalene, determining catechol oxidation via the meta-pathway].

Most of the known naphthalene biodegradation plasmids determine the process of naphthalene degradation via salicylate and catechol using the meta pathway of catechol degradation. However, Pseudomonas putida strains with plasmids pBS2, pBS216, pBS217 and NPL-1 exert no activity of the enzymes involved in the meta pathway of catechol degradation. When 2-methylnaphthalene was added to the medium as a sole carbon source, mutants growing on this compound were isolated in the strains with the studied plasmids. Plasmid localization of the mutations was established using conjugation transfer as well as by obtaining spontaneous variants that had lost the ability to grow on 2-methylnaphthalene; the respective plasmid mutants were referred to as pBS101, pBS102, pBS103 and pBS105. The strains with the mutant plasmids were tested for the activity of the key enzymes involved in naphthalene catabolism and the activity of catechol-2,3-dioxygenase was found. The data allow one to arrive at the conclusion that plasmids pBS2, pBS216, pBS217 and NPL-1 contain silent genes for the meta pathway of catechol degradation, which are activated by the respective mutations.

Biodegradation, Environmental↗
PubMed1986

Serum lipid peroxide levels of albino rats administered naphthalene.

When naphthalene was administered at a daily dose of 1 g/kg body weight to Wistar strain rats, their serum lipid peroxide levels were increased on the 4th day after the first administration and reached a maximum on the 7th day. This seems to be due to lipid peroxidation in the liver, in which lipid peroxide levels were increased in a similar pattern as those in the serum. The content of reduced glutathione in lenses of naphthalene-administered rats decreased on the 4th day. These results suggest that in naphthalene-induced cataract in albino rats increased lipid peroxides in the bloodstream may play a role in cataractogenesis.

Animals↗
PubMedDate not supplied

[Regulation of the synthesis of the key enzymes for naphthalene catabolism in Pseudomonas putida and Pseudomonas fluorescens carrying the biodegradation plasmids NAH, pBS3, pBS2 and NPL-1].

Regulation of the synthesis of key enzymes catalysing naphthalene catabolism was studied in Pseudomonas strains containing different plasmids of naphthalene biodegradation. The synthesis of naphthalene oxygenase, salicylate hydroxylase, catechol-1,2-oxygenase and cathechol-2,3-oxygenase was shown to be regulated in both the coordinated and non-coordinated manner.

Biodegradation, Environmental↗
PubMed1985

Differential stereoselectivity of cytochromes P-450b and P-450c in the formation of naphthalene and anthracene 1,2-oxides. The role of epoxide hydrolase in determining the enantiomer composition of the 1,2-dihydrodiols formed.

As is the case for cytochrome P-450c, arene 1,2-oxides have been identified as initial metabolites when naphthalene and anthracene are oxidized by cytochrome P-450b in a highly purified, reconstituted system. Overall rates of metabolism by cytochrome P-450b are greater than 3-fold and greater than 50-fold lower than the respective rates of metabolism by cytochrome P-450c. For both hydrocarbons, the (-)-(1S,2R)-oxide predominates (74%) with cytochrome P-450b as the terminal oxidant, based on trapping the labile arene oxides as N-acetyl-L-cysteine S-conjugates of known absolute configuration. This result is in marked contrast to data obtained with cytochrome P-450c where the (+)-(1R,2S)-oxides predominate (73-greater than 95%). In the absence of added epoxide hydrolase, the metabolically formed arene oxides rapidly isomerize to phenols. Addition of increasing amounts of epoxide hydrolase to the incubation medium results in the formation of trans-1,2-dihydrodiols at the expense of phenols from the common arene oxide intermediates. Evaluation of the kinetic parameters (Km and kcat) for the hydration of the (+)- and (-)-enantiomers of both arene oxides by epoxide hydrolase has indicated that the (+)-(1R,2S)-enantiomers exhibit lower values of Km (approximately 1 microM) whereas the values of kcat are similar for both enantiomers of a given arene oxide. These parameters have allowed construction of a mathematical model which predicts the enantiomer composition of the dihydrodiols formed from naphthalene in reconstituted systems containing specific epoxide hydrolase concentrations. The data reported argue against a selective functional coupling mechanism between cytochrome P-450c and epoxide hydrolase in the metabolism of naphthalene and anthracene to the 1,2-dihydrodiols.

Animals↗
PubMedDate not supplied

Identification of new sulfur-containing metabolites of naphthalene in mouse urine.

Seven acidic sulfur-containing metabolites were isolated from mouse urine following administration of naphthalene. The metabolites have been identified as (1-hydroxy-1,2-dihydro-2-naphthalenylthio)acetic acid (I), 2-hydroxy-3-(1-hydroxy-1,2-dihydro-2-naphthalenylthio)propanoic acid (II), (1,2,3-trihydroxy-1,2,3,4-tetrahydro-4-naphthalenylthio)acetic acid (III), and N-acetyl-S-(1-hydroxy-1,2-dihydro-2-naphthalenyl)-L-cysteine (IV). The dehydration products of I, II, and IV, namely 1-(naphthalenylthio)acetic acid (V), 2-hydroxy-3-(1-naphthalenylthio)propanoic acid (VI), and N-acetyl-S-(1-naphthalenyl)-L-cysteine (VII), respectively, were also present in several urinary extracts. Nine methylthio derivatives were identified in the neutral extract of urine. These metabolites were the following: 1-methylthionaphthalene, trans-1-hydroxy-2-methylthio-1,2-dihydronaphthalene, two stereoisomeric 1,2,3-trihydroxy-4-methylthio-1,2,3,4-tetrahydronaphthalenes, 1,3-di(methylthio)-2,4-dihydroxy-1,2,3,4-tetrahydronaphthalene, 1,4-di(methylthio)-2,3-dihydroxy-1,2,3,4-tetrahydronaphthalene, two methylthiohydroxy-naphthalenes, and a methylthiodihydroxydihydronaphthalene. Following intraperitoneal administration of N-acetyl-S-(1-hydroxy-1,2-dihydro-2-naphthalenyl)-L-cysteine to mice, the acidic metabolites I, II, and unchanged IV were found. The gas-chromatographic and gas chromatographic-mass spectral properties of the methyl ester-trimethylsilyl derivatives of the acidic sulfur metabolites of naphthalene are presented.

Animals↗
PubMedDate not supplied

Capillary gas chromatographic determination of naphthalene in bran and wheat germ products.

A method is described for determining naphthalene in bran and wheat germ products. The method involves distilling the naphthalene from a water-cereal mixture and then extracting the distillate with hexane. A 10 microL aliquot of the hexane extract is injected into a gas chromatograph equipped with a capillary column. Dodecan-1-ol is used as the internal standard. Mean recoveries, standard deviations (SD), and coefficients of variation (CV) for samples of unprocessed bran, unprocessed wheat germ, bran flakes breakfast cereal, and sultana bran breakfast cereal, spiked with naphthalene at various levels, were 1.0 ppm spike, mean 0.98, SD 0.09, CV 9.5%; 2.5 ppm spike, mean 2.37, SD 0.22, CV 9.4%; 5.0 ppm spike, mean 4.86, SD 0.19, CV 4.0%; 10 ppm spike, mean 9.25, SD 0.38, CV 4.1%. The mean recoveries exceeded 90% in each case. The detection limit for the method was about 0.5 ppm.

Chromatography, Gas↗
PubMedDate not supplied

[Thermosensitivity of naphthalene biodegradation plasmids].

The object of the work was to study the functional expression of naphthalene and salicylic acid catabolism systems and the stability of naphthalene biodegradation plasmids NAH, pBS2, pBS3 and NPL-41 in Pseudomonas aeruginosa PAO. The catabolic systems of the plasmids were shown to be thermosensitive, with a slight variation between one another. The plasmids became unstable at a high temperature; the temperature of effective elimination was 41 degrees C for plasmids NPL-41 and pBS3, and 42 degrees C for plasmids NAH and pBS2. NAH and pBS2 produced a weak inhibiting effect while NPL-41 and pBS3 caused a strong inhibition of the PAO strain growth at 42 degrees C. As a result, many anomalous filamentous cells (partly in the state of lysis) appeared in the cultural broth. Only PAO cells that had lost their plasmid were capable of normal growth in a medium with MPA at an elevated temperature; this creates a convenient system for selection of clones that have lost the plasmids of naphthalene biodegradation. Some of these plasmids can inhibit growth of Pseudomonas strains at an elevated temperature; this fact should be taken into account when the capability of Pseudomonas to grow at a high temperature is used as a taxonomic feature.

Adaptation, Physiological↗
PubMed1984

Stereoselectivity of cytochrome P-450c in the formation of naphthalene and anthracene 1,2-oxides.

Absolute configurations of the arene 1,2-oxides formed from napththalene and anthracene by cytochrome P-450c, the predominant isozyme of cytochrome P-450 found in the livers of rats treated with 3-methylcholanthrene, were determined via two different approaches. The first consisted of trapping the arene oxides with N-acetyl-L-cysteine to form S-conjugates, methylation of the conjugates with diazomethane, and separation of the resulting diastereomeric esters by reversed phase high performance liquid chromatography. Analysis by this procedure of the arene oxides formed from radioactive naphthalene and anthracene by a highly purified and reconstituted monooxygenase system containing cytochrome P-450c indicated that 73 and greater than or equal to 95%, respectively, of the metabolically formed arene oxides consisted of the (+)-(1R,2S)-enantiomer. In the second approach, each hydrocarbon was incubated with a reconstituted system containing both cytochrome P-450c and epoxide hydrolase. Under these conditions, the predominant metabolites are trans-1,2-dihydrodiols formed by epoxide hydrolase catalyzed trans-addition of water to the arene oxide intermediates. In both cases, the (-)-(1R,2R)-dihydrodiols predominated; 92% for naphthalene and 99% for anthracene. Enzyme-catalyzed addition of water to (+)- and (-)-anthracene 1,2-oxide and (+)-napthalene 1,2-oxide occurred exclusively (greater than 99%) at the allylic 2-position. The (-)-(1S,2R)-naphthalene 1,2-oxide, however, is converted to a 40:60 mixture of the (-)-(1R,2R)- and (+)-(1S,2S)-dihydrodiols by benzylic and allylic attack, respectively, resulting in increased enantiomeric purity of the dihydrodiol relative to the oxide. Thus, qualitatively and quantitatively both approaches indicate that the (+)-arene (1R,2S)-oxides predominate. The results are discussed in terms of the steric constraints of a proposed model for the catalytic binding site of cytochrome P-450c.

Animals↗