A mechanism of action for the inhibition of black pigment dispersion in the fiddler crab, Uca pugilator, by naphthalene

The polycyclic aromatic hydrocarbon, naphthalene, inhibits the circadian dispersion of epidermal black pigment in the fiddler crab, Uca pugilator, by inhibiting the release of black pigment dispersing hormone. Naphthalene caused no permanent neural damage in Uca pugilator. Naphthalene did not cause a chemically-induced phase shift in the circadian rhythm of black pigment dispersion but reduced the daytime peak of that dispersion. Black pigment concentration, which occurs at night, was not affected by exposure to naphthalene. Black pigment dispersing hormone in naphthalene-exposed crabs can be released by an injection of norepinephrine. Given the points above, and previously published data, it is concluded that naphthalene inhibits circadian black pigment dispersion in Uca pugilator by inhibiting the release of the neurotransmitter, norepinephrine.     

Simultaneous Quantification of Multiple Urinary Naphthalene Metabolites by Liquid Chromatography Tandem Mass Spectrometry

Naphthalene is an environmental toxicant to which humans are exposed. Naphthalene causes dose-dependent cytotoxicity to murine airway epithelial cells but a link between exposure and human pulmonary disease has not been established. Naphthalene toxicity in rodents depends on P450 metabolism. Subsequent biotransformation results in urinary elimination of several conjugated metabolites. Glucuronide and sulfate conjugates of naphthols have been used as markers of naphthalene exposure but, as the current studies demonstrate, these assays provide a limited view of the range of metabolites generated from the parent hydrocarbon. Here, we present a liquid chromatography tandem mass spectrometry method for measurement of the glucuronide and sulfate conjugates of 1-naphthol as well as the mercapturic acids and N-acetyl glutathione conjugates from naphthalene epoxide. Standard curves were linear over 2 log orders. On column detection limits varied from 0.91 to 3.4 ng; limits of quantitation from 1.8 to 6.4 ng. The accuracy of measurement of spiked urine standards was -13.1 to + 5.2% of target and intra-day and inter-day variability averaged 7.2 (± 4.5) and 6.8 (± 5.0) %, respectively. Application of the method to urine collected from mice exposed to naphthalene at 15 ppm (4 hrs) showed that glutathione-derived metabolites accounted for 60-70% of the total measured metabolites and sulfate and glucuronide conjugates were eliminated in equal amounts. The method is robust and directly measures several major naphthalene metabolites including those derived from glutathione conjugation of naphthalene epoxide. The assays do not require enzymatic deconjugation, extraction or derivatization thus simplifying sample work up.     

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.     

Prevention of naphthalene-induced pulmonary toxicity by glutathione prodrugs: roles for glutathione depletion in adduct formation and cell injury

Naphthalene is metabolized in the lung and liver to reactive intermediates by cytochrome P450 enzymes. These reactive species deplete glutathione, covalently bind to proteins, and cause necrosis in Clara cells of the lung. The importance of glutathione loss in naphthalene toxicity was investigated by using the glutathione prodrugs (glutathione monoethylester or cysteine-glutathione mixed disulfide) to maintain glutathione pools during naphthalene exposure. Mice given a single intraperitoneal injection of naphthalene (1.5 mmol/kg) were treated with either prodrug (2.5 mmol/kg) 30 min later. Both compounds effectively maintained glutathione levels and decreased naphthalene-protein adducts in the lung and liver. However, cysteine-glutathione mixed disulfide was more effective at preventing Clara cell injury. To study the prodrugs in Clara cells without the influence of hepatic naphthalene metabolism and circulating glutathione, dose-response and time-course studies were conducted with intrapulmonary airway explant cultures. Only the ester of glutathione raised GSH in vitro; however, both compounds limited protein adducts and cell necrosis. In vitro protection was not associated with decreased naphthalene metabolism. We conclude that (1) glutathione prodrugs can prevent naphthalene toxicity in Clara cells, (2) the prodrugs effectively prevent glutathione loss in vivo, and (3) cysteine-glutathione mixed disulfide prevents naphthalene injury in vitro without raising glutathione levels.     

Naphthalene uptake by a Pseudomonas fluorescens isolate

The uptake of naphthalene has been investigated in the metabolizing cells of Pseudomonas fluorescens utilizing [1-14C]naphthalene. The uptake displayed an affinity constant (Kt) of 11 microM and a maximal velocity (Vmax) of 17 nmol.h-1.mg-1 cellular dry weight. Naphthalene uptake was not observed in a mutant strain, TG-5, which was unable to utilize naphthalene as a sole source of carbon for growth. Uptake was significantly inhibited (approximately 90%) by the presence of growth-inhibiting levels of either azide or 2,4-dinitrophenol and was sensitive to the presence of structural analogues of naphthalene. The intracellular levels of ATP were not significantly reduced by the presence of either azide or 2,4-dinitrophenol. The presence of alpha-naphthol was found to noncompetitively inhibit naphthalene uptake, displaying a Ki of 0.041 microM. It is concluded that the first step in the utilization of naphthalene by Pseudomonas fluorescens is its transport into the cell by a specific energy-linked transport system.     

Degradation of polycyclic aromatic hydrocarbons by pure strains and by defined strain associations: inhibition phenomena and cometabolism

Six bacterial strains capable of using, as sole carbon and energy source, at least one of the following polycyclic aromatic hydrocarbons (PAH), naphthalene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene, were isolated. The interactions between these PAH during their biodegradation were studied in experiments involving PAH pairs, one PAH at least being used as a carbon source. All individual strains were found capable of cometabolic degradation of PAH in a range varying among strains. Inhibition phenomena, sometimes drastic, were often observed but synergistic interactions were also detected. Naphthalene was toxic to all strains not isolated on this compound. Strain associations were found efficient in relieving inhibition phenomena, including the toxic effect of naphthalene. Accumulation of water-soluble metabolites was consistently observed during PAH degradation.     

Naphthalene biodegradation in environmental microcosms: estimates of degradation rates and characterization of metabolites

Naphthalene biodegradation was investigated in microcosms containing sediment and water collected from three ecosystems which varied in past exposure to anthropogenic and petrogenic chemicals. Mineralization half-lives for naphthalene in microcosms ranged from 2.4 weeks in sediment chronically exposed to petroleum hydrocarbons to 4.4 weeks in sediment from a pristine environment. Microbiological analysis of sediments indicated that hydrocarbon-utilizing microbial populations also varied among ecosystems and were 5 to 12 times greater in sediment after chronic petrogenic chemical exposure than in sediment from an uncontaminated ecosystem. Sediment from an ecosystem exposed to agricultural chemicals had a mineralization half-life of 3.2 weeks for naphthalene and showed about a 30-fold increase in heterotrophic bacterial populations in comparison to uncontaminated sediments, but only a 2- to 3-fold increase in hydrocarbon-degrading bacteria. Analysis of organic solvent-extractable residues from the microcosms by high-pressure liquid chromatography detected polar metabolites which accounted for 1 to 3% of the total radioactivity. Purification of these residues by thin-layer chromatography and further analysis by gas chromatography-mass spectrometry indicated that cis-1,2-dihydroxy-1,2-dihydronaphthalene, 1-naphthol, salicylic acid, and catechol were metabolites of naphthalene. These results provide useful estimates for the rates of naphthalene mineralization in different natural ecosystems and on the degradative pathway for microbial metabolism of naphthalene in freshwater and estuarine environments.     

Naphthalene biodegradation in environmental microcosms: estimates of degradation rates and characterization of metabolites.

Naphthalene biodegradation was investigated in microcosms containing sediment and water collected from three ecosystems which varied in past exposure to anthropogenic and petrogenic chemicals. Mineralization half-lives for naphthalene in microcosms ranged from 2.4 weeks in sediment chronically exposed to petroleum hydrocarbons to 4.4 weeks in sediment from a pristine environment. Microbiological analysis of sediments indicated that hydrocarbon-utilizing microbial populations also varied among ecosystems and were 5 to 12 times greater in sediment after chronic petrogenic chemical exposure than in sediment from an uncontaminated ecosystem. Sediment from an ecosystem exposed to agricultural chemicals had a mineralization half-life of 3.2 weeks for naphthalene and showed about a 30-fold increase in heterotrophic bacterial populations in comparison to uncontaminated sediments, but only a 2- to 3-fold increase in hydrocarbon-degrading bacteria. Analysis of organic solvent-extractable residues from the microcosms by high-pressure liquid chromatography detected polar metabolites which accounted for 1 to 3% of the total radioactivity. Purification of these residues by thin-layer chromatography and further analysis by gas chromatography-mass spectrometry indicated that cis-1,2-dihydroxy-1,2-dihydronaphthalene, 1-naphthol, salicylic acid, and catechol were metabolites of naphthalene. These results provide useful estimates for the rates of naphthalene mineralization in different natural ecosystems and on the degradative pathway for microbial metabolism of naphthalene in freshwater and estuarine environments.     

Radiolytic Studies of Naphthalene in the Presence of Water

Naphthalene is an interesting candidate to study in the framework of organic delivery to planetary surfaces as well as in the origin of life. Additionally, naphthalene is of environmental interest, because of its chronic and acute effects on living systems, such as humans and animals (e.g. moths). Naphthalene has been well studied in both fields. In this paper we give an overview of radiolytic studies of naphthalene in the presence of both liquid water and water ice. From our review it appears that OH radicals are formed both in liquid water and in interstellar ices and that these radicals play a considerable role in the degradation of naphthalene. However, it also appears that upon irradiation of naphthalene in liquid water, hydrogen peroxide, a species that accelerates naphthalene degradation, is formed. Based on this review we suggest that the role of hydrogen peroxide in interstellar ices should be further investigated.     

Biodegradation of naphthalene in aqueous nonionic surfactant systems.

The principal objective of this study was to quantify the bioavailability of micelle-solubilized naphthalene to naphthalene-degrading microorganisms comprising a mixed population isolated from contaminated waste and soils. Two nonionic surfactants were used, an alkylethoxylate, Brij 30 (C12E4), and an alkylphenol ethoxylate, Triton X-100 (C8PE9.5). Batch experiments were used to evaluate the effects of aqueous, micellized nonionic surfactants on the microbial mineralization of naphthalene and salicylic acid, an intermediate compound formed in the pathway of microbial degradation of naphthalene. The extent of solubilization and biodegradation under aerobic conditions was monitored by radiotracer and spectrophotometric techniques. Experimental results showed that surfactant concentrations above the critical micelle concentration were not toxic to the naphthalene-degrading bacteria and that the presence of surfactant micelles did not inhibit mineralization of naphthalene. Naphthalene solubilized by micelles of Brij 30 or Triton X-100 in liquid media was bioavailable and degradable by the mixed culture of bacteria.     

Naphthalene and Benzene Degradation under Fe(III)-Reducing Conditions in Petroleum-Contaminated Aquifers

Naphthalene was oxidized anaerobically to CO₂ in sediments collected from a petroleum-contaminated aquifer in Bemidji, Minnesota in which Fe(III) reduction was the terminal electron-accepting process. Naphthalene was not oxidized in sediments from the methanogenic zone at Bemidji or in sediments from the Fe(III)-reducing zone of other petroleum-contaminated aquifers studied. In a profile across the Fe(III)-reducing zone of the Bemidji aquifer, rates of naphthalene oxidation were fastest in sediments with the highest proportion of Fe(III), which was also the zone of the most rapid degradation of benzene, toluene, and acetate. The comparative studies attempted to elucidate factors that might account for the fact that unsubstituted aromatic hydrocarbons such as benzene and naphthalene were degraded under Fe(III)-reducing conditions at Bemidji, but not at the other aquifers examined. These studies indicated that the ability of Fe(III)-reducing microorganisms to degrade benzene and naphthalene at the Bemidji site cannot be attributed to groundwater components that make Fe(III) more available for reduction or other potential factors that were evaluated. However, unlike the other aquifers evaluated, uncontaminated sediments at the Bemidji site could be adapted for anaerobic benzene degradation merely with the addition of benzene. These findings indicate that Bemidji sediments naturally contain Fe(III) reducers capable of degradation of unsubstituted aromatic hydrocarbons.     

Naphthalene,phenanthrene and surfactant biodegradation

The impact of surfactants on naphthalene and phenanthrene biodegradation and vice versa after surfactant flushing were evaluated using two anionic surfactants: sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS); and two nonionic surfactants: POE (20) sorbitan monooleate (T-maz-80) and octylphenol poly(ethyleneoxy) ethanol (CA-620). Naphthalene and phenanthrene biodegradation varied differently in the presence of different surfactants. Naphthalene biodegradation was not impacted by the presence of SDS. In the presence of T-maz-80 and CA-620, naphthalene biodegradation occurred at a lower rate (0.14 d^-1 for T-maz-80 and 0.19 d^-1 for CA-620) as compared to un-amended control (0.29 d^-1). Naphthalene biodegradation was inhibited by the presence of SDBS. In the presence of SDS, phenanthrene biodegradation occurred at a lower rate (0.10 d^-1 as compared to un-amended control of 0.17 d^-1) and the presence of SDBS, CA-620 and T-maz-80 inhibited phenanthrene biodegradation. The surfactants also responded differently to the presence of naphthalene and phenanthrene. In the presence of naphthalene, SDS biodegradation was inhibited; SDBS and T-maz-80 depleted at a lower rate (0.41d^-1 and 0.12 d^-1 as compared to 0.48 d^-1 and 0.22 d^-1). In the absence of naphthalene, CA-620 was not degradable, while in the presence of naphthalene, CA-620 began to degrade at a comparatively low rate (0.12 d^-1). In the presence of phenanthrene, SDS biodegradation occurred at a lower rate (1.2 d^-1 as compared to 1.68 d^-1) and a similar trend was observed for T-maz-80. The depletion of SDBS and CA-620 did not change significantly. The choice of SDS for naphthalene-contaminated sites would not adversely affect the natural attenuation of naphthalene, in addition, naphthalene was preferentially utilized to SDS by naphthalene-acclimated microorganisms. Therefore, SDS was the best choice. T-maz-80 was also found to be usable in naphthalene-contaminated sites. For phenanthrene contaminated sites, SDS was the only choice.     

Metabolism of naphthalene, 2-methylnaphthalene, salicylate, and benzoate by Pseudomonas PG: regulation of tangential pathways.

Naphthalene is metabolized by Pseudomonas PG through 1,2-dihydroxynaphthalene and salicylate to catechol, which is then degraded by the meta pathway. 2-Methylnaphthalene, but not 1-methylnaphthalene, also serves as a growth substrate and is metabolized by the same route, through 4-methylcatechol. The same nonspecific meta pathway enzymes appear to be induced by growth on either naphthalene or 2-methylnaphthalene. The level to which 2-hydroxymuconic semialdehyde hydrolase is induced is low and probably of no metabolic significance. Growth on salicylate or catechol, both intermediates of naphthalene degradation, or benzoate results in induction of the ortho pathway, the alternative route for catechol dissimilation. No induction of 1,2-dihydroxynaphthalene oxygenase was found in salicylate-grown cells. Anaerobic growth on a succinate-nitrate medium in the presence of various inducers indicates that cis, cis-muconate, or one of its metabolites is the inducer of the ortho pathway enzymes. The inducer or inducers of the early enzymes of naphthalene degradation and of the meta pathway enzymes must be an early intermediate of the naphthalene pathway above salicylate.     

Dynamic response of naphthalene biodegradation in a continuous flow soil slurry reactor

Periodic perturbations were used to evaluate the system stability and robustness of naphthalene biodegradation in a continuous flow stirred tank reactor (CSTR) containing a soil slurry. The experimental design involved perturbing the test system using a sinusoidal input either of naphthalene or non-naphthalene organic carbon at different frequencies during steady state operation of the reactors. The response of the test system was determined by using time series off-gas analysis for naphthalene liquid phase concentration and degradation, total viable cell counts, and gene probe analysis of naphthalene degradative genotype, and by batch mineralization assays.Naphthalene biodegradation rates were very high throughout the experimental run (95 to >99% removed) resulting in very low or undetectable levels of naphthalene in the off-gas and reactor effluent. Attempts to reduce the rate of naphthalene biotransformation by either reducing the reactor temperature from 20°C to 10°C or the dissolved oxygen level (>1 mg/L) were unsuccessful. Significant naphthalene biodegradation was observed at 4°C. While variable, the microbial community as measured by population densities was not significantly affected by temperature changes. In terms of naphthalene biotransformation, the system was able to adapt readily to all perturbations in the reactor.Department of Chemical EngineeringDepartment of Microbiology and The Graduate Program in EcologyDepartment of Civil Engineering, New Orleans University     

萘及其衍生物对普通小球藻的毒性效应

本文研究了萘及其衍生物(萘、1-萘酚、2-萘酚和1-萘胺)对普通小球藻的生长、叶绿素含量、光合强度和呼吸强度的影响。萘、1-萘酚和1-萘胺在低浓度下能促进普通小球藻的生长,高浓度则抑制藻的生长;2-萘酚在实验浓度下都抑制藻的生长。萘、1-萘酚、2-萘酚和1-萘胺的96hEC_(50)分别为98.06、11.87、13.39和6.95mg/L。萘及其衍生物对叶绿素含量和光合强度的影响比对生长的影响强,而对叶绿素含量的影响又比对光合强度的影响强。可以这样认为:萘及其衍生物对普通小球藻生长的抑制是通过抑制藻叶绿素a的形成,进而降低光合强度实现的。低浓度的萘和1-萘酚增强普通小球藻的呼吸强度,而高浓度则减弱;与此相反,低浓度的2-萘酚对藻的呼吸强度影响不大,高浓度能显著增强;在实验浓度下的1-萘胺使藻呼吸强度明显减弱,但随着时间的推移,呼吸强度出现回升,且高浓度回升较快。     

Metabolism of Naphthalene, 1-Naphthol, Indene, and Indole by Rhodococcus sp. Strain NCIMB 12038

The regulation of naphthalene and 1-naphthol metabolism in a Rhodococcus sp. (NCIMB 12038) has been investigated. The microorganism utilizes separate pathways for the degradation of these compounds, and they are regulated independently. Naphthalene metabolism was inducible, but not by salicylate, and 1-naphthol metabolism, although constitutive, was also repressed during growth on salicylate. The biochemistry of naphthalene degradation in this strain was otherwise identical to that found in Pseudomonas putida, with salicylate as a central metabolite and naphthalene initially being oxidized via a naphthalene dioxygenase enzyme to cis-(1R,2S)-1,2-dihydroxy-1,2-dihydronaphthalene (naphthalene cis-diol). A dioxygenase enzyme was not expressed under growth conditions which facilitate 1-naphthol degradation. However, biotransformations with indene as a substrate suggested that a monooxygenase enzyme may be involved in the degradation of this compound. Indole was transformed to indigo by both naphthalene-grown NCIMB 12038 and by cells grown in the absence of an inducer. Therefore, the presence of a naphthalene dioxygenase enzyme activity was not necessary for this reaction. Thus, the biotransformation of indole to indigo may be facilitated by another type of enzyme (possibly a monooxygenase) in this organism.     

Effects of different nitrogen sources on lignocellulose degradation and APPL production

Naphthalene utilizing bacteria were isolated from several sites above and below the discharge from a coking plant. The distribution of the bacteria was influenced by the effluent. Of these isolates, 11·4% obtained from the effluent discharge site, contained plasmids. No conjugal transfer of naphthalene utilizing ability was observed in over 1000 matings. Curing and transformation experiments demonstrated that one plasmid pNB33 (101 kb) was concerned with naphthalene catabolism.     

Oxidation of carbazole to 3-hydroxycarbazole by naphthalene 1,2-dioxygenase and biphenyl 2,3-dioxygenase

Abstract Naphthalene 1,2-dioxygenase from Pseudomonas sp. NCIB 9816-4 and biphenyl dioxygenase from Beijerinckia sp. B8/36 oxidized the aromatic N-heterocycle carbazole to 3-hydroxycarbazole. Toluene dioxygenase from Pseudomonas putida F39/D did not oxidize carbazole. Transformations were carried out by mutant strains which oxidize naphthalene and biphenyl to cis -dihydrodiols, and with a recombinant E. coli strain expressing the structural genes of naphthalene 1,2-dioxygenase from Pseudomonas sp. NCIB 9816-4. 3-Hydroxycarbazole is presumed to result from the dehydration of an unstable cis -dihydrodiol.