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 73 records · Page 4Linked to original sources
PubMed2001

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 (0.41 d(-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.

Biodegradation, Environmental↗
PubMed2001

Enhanced degradation of naphthalene by immobilization of Pseudomonas sp. strain NGK1 in polyurethane foam.

A Pseudomonas sp. strain NGKI (NCIM 5120) capable of degrading naphthalene was immobilized in polyurethane foam. The naphthalene-degrading activity of the freely suspended cells was compared with that of immobilized cells in batches in shaken culture and in a continuous culture system in a packed-bed reactor. Increasing concentrations of naphthalene were better tolerated and more quickly degraded by immobilized cell cultures than by free cells. An initial naphthalene concentration of 25 mM was completely degraded by freely suspended cells (4 x 10(10) cfu ml(-1)) and polyurethane-foam-immobilized cells (0.8-1 x 10(12) cfu g(-1) foam cubes) after 4 days and 2 days of incubation, respectively. Free cells degraded a maximum of 30 mM naphthalene after 4 days of incubation with 50 mM naphthalene, and no further degradation was observed even after 15 days of incubation, whereas foam-immobilized cells brought about the complete degradation of 50 mM initial naphthalene after 6 days of incubation. Furthermore, with 25 mM naphthalene, the polyurethane-foam-immobilized cells were re-used 45 times over a period of 90 days without losing naphthalene-degrading activity. By contrast, with the same amount of naphthalene, alginate-, agar-, and polyacrylamide-entrapped cells could be reused for 18, 12, and 23 times over a period of 44, 28, and 50 days, respectively. During continuous degradation in a packed-bed reactor, foam-immobilized cells degraded 80 mM naphthalene at a rate of 150 ml(-1) h(-1). With the same flow rate and 40 mM naphthalene, this system operated efficiently and continuously for about 120 days, whereas the packed-bed reactor with alginate-, agar-, and polyacrylamide-entrapped cells could be operated only for 45, 40, and 60 days respectively. Thus, more efficient degradation of naphthalene could be achieved by immobilizing cells of Pseudomonas sp. strain NGK1 in polyurethane foam, rather than in the other matrices tested.

Cell Count↗
PubMed2002

Survival and naphthalene-degrading activity of Rhodococcus sp. strain 1BN in soil microcosms.

AIMS: The survival and activity of Rhodococcus sp. strain 1BN, inoculated into naphthalene-contaminated sandy-loam soil microcosms, were studied using classical and molecular methods. METHODS AND RESULTS: The naphthalene-degrading activity of 1BN in microcosms was examined through viable counts, CO2 production and naphthalene consumption, while its survival after inoculation was monitored by detecting the contemporary presence of alkane and naphthalene degradative genes and by analysing the 16S rDNA specific restriction profile. The inoculation of 1BN did not significantly enhance naphthalene degradation in the naphthalene-contaminated native soil, where 1BN maintained its catabolic activity also when in the presence of indigenous microflora. Instead the rate of naphthalene degradation by the inoculated 1BN was greater in sterile naphthalene-contaminated soil. The level of 1BN was only slightly higher after inoculation regardless of whether indigenous naphthalene-degrading bacteria were present or not and 1BN remained viable even when the substrate was depleted. CONCLUSIONS: This study documents the colonization and growth of 1BN in a non-sterile, naphthalene-added, sandy-loam soil having an active indigenous naphthalene-degrading population. SIGNIFICANCE AND IMPACT OF THE STUDY: An active and well-established naphthalene-degrading bacterial population in the native soil did not hamper the survival of the introduced 1BN that, through its activity, enhanced the mineralization rate of naphthalene.

Cytochrome P-450 CYP4A↗
PubMedDate not supplied

Genetic toxicity of naphthalene: a review.

Results of five previously unpublished studies of the genotoxicity of naphthalene are presented and extensively discussed in relation to the large database that exists in the published literature. According to the published literature, naphthalene has not induced gene mutations in bacterial assays or in a metabolically competent human cell line. However, naphthalene has caused cytotoxicity in some cell lines, and induced clastogenicity in Chinese hamster ovary (CHO) cells, in a human lymphoblastoid cell line, and in preimplantation mouse embryos. Some naphthalene metabolites were cytotoxic, but only naphthoquinones produced chromosomal damage in vitro. No chromosomal damage was observed in vivo in bone marrow erythrocytes from treated mice; however, a positive response was reported in a Drosophila assay for wing somatic mutation and recombination. The five unpublished studies of naphthalene genotoxicity include three studies in vitro (two Ames bacterial assays and an in vitro unscheduled DNA synthesis assay) and two in vivo (mouse micronucleus and in vivo unscheduled DNA synthesis). Naphthalene was inactive in all five studies, in agreement with reports in the published literature. Chronic inhalation of naphthalene over 2 yr induced an increased incidence of benign alveolar/bronchial adenomas in female mice, and nasal epithelial tumors in both sexes of rats. Inflammation, tissue damage, and subsequent regenerative hyperplasia at target organ sites occurred in both species. Results of standard genetic toxicity assays suggest that naphthalene is not likely to be genotoxic in vivo. Since the in vitro results come primarily from assays utilizing liver-mediated activation systems, and the in vivo results come from rodent organs that are not targets for tumors, tests using naphthalene-sensitive rodent tissues would determine the applicability of current data in addressing the mechanisms of these species and site-specific cancers. The standard assays reported here may be useful in predicting potential health hazard in other species, or in humans, in whom there are few reported instances of naphthalene-induced cancer, especially as more data on species-specific differences in naphthalene metabolism become available. Despite present data limitations, a threshold mechanism for tumorigenesis can be proposed. The absence of naphthalene-induced gene mutation and the presence of cytotoxicity and some chromosomal events in vitro are consistent with a threshold-related mechanism of tumor induction, driven by cytotoxicity and cell regeneration, followed by genetic events, or by accumulation of naphthalene at specific target sites to allow in situ formation of a genotoxic metabolite to trigger or enhance spontaneous tumor development.

Animals↗
PubMed2002

Pseudomonas putida strain PCL1444, selected for efficient root colonization and naphthalene degradation, effectively utilizes root exudate components.

Previously, we have described the selection of a plant-bacterium pair that is efficient in rhizoremediating naphthalene pollution in microcosm studies. After repeated selection for efficient root tip colonization upon inoculation of seeds of grass cv. Barmultra and for stable and efficient growth on naphthalene, Pseudomonas putida PCL1444 was selected as the most efficient colonizer of Barmultra roots. Here, we report the analysis of Barmultra root exudate composition and our subsequent tests of the growth rate of the bacterium and of the expression of the naphthalene degradation genes on individual exudate components. High performance liquid chromatography analysis of the organic acid and sugar root-exudate components revealed that glucose and fructose are the most abundant sugars, whereas succinic acid and citric acid are the most abundant organic acids. Tn5luxAB mutants of PCL1444 impaired in naphthalene degradation appeared to be impaired in genes homologous to genes of the upper naphthalene degradation pathway present in various Pseudomonas strains and to genes of the lower pathway genes for naphthalene degradation in P. stutzeri. Highest expression for both pathways involved in naphthalene degradation during growth in minimal medium with the carbon source to be tested was observed at the start of the logarithmic phase. Naphthalene did not induce the upper pathway, but a different pattern of expression was observed in the lower pathway reporter, probably due to the conversion of naphthalene to salicylic acid. Salicylic acid, which is described as an intermediate of the naphthalene degradation pathway in many Pseudomonas strains, did induce both pathways, resulting in an up to sixfold higher expression level at the start of the logarithmic phase. When expression levels during growth on the different carbon sources present in root exudate were compared, highest expression was observed on the two major root exudate components, glucose and succinic acid. These results show an excellent correlation between successful naphthalene rhizoremediation by the Barmultra-P. putida PCL1444 pair and both efficient utilization of the major exudate components for growth and high transcription of the naphthalene catabolic genes on the major exudate components. Therefore, we hypothesize that efficient root colonizing and naphthalene degradation is the result of the applied colonization enrichment procedure.

Carbon↗
PubMed1997

Urinary naphthols as an indicator of exposure to naphthalene.

OBJECTIVE: The relationship between exposure to naphthalene and urinary excretion of naphthols was examined. METHODS: Concentrations of naphthalene and naphthols in breathing-zone air during a workshift and 1-naphthol and 2-naphthol in urine collected after the workshift were determined for 102 male workers. Gas chromatography with a flame ionization detector (GC-FID) was used to determine the air concentration. Urine naphthols were extracted after acid hydrolysis by solid-phase extraction and separated by the GC-FID method. Naphthalene homologues in air and their metabolites in urine samples were identified by gas chromatography-mass spectrometry. RESULTS: 1-Naphthol, 2-naphthol and 1,4-naphthoquinone were identified in the urine samples. The time-weighted average concentrations of naphthalene and naphthols in the breathing-zone air showed that the exposure level of the workers was rather low. The geometric mean values were as follows: 0.77 and 0.87 mg/m3 for naphthalene, 0.016 and 0.034 mg/m3 for 1-naphthol, 0.012 and 0.067 mg/m3 for 2-naphthol during tar distillation and naphthalene oil distillation, respectively. The corresponding urinary concentrations of 1- and 2-naphthols were 693.1 and 264.4 micromol/mol and 264.4 and 297.7 micromol/mol creatinine, respectively. The correlation coefficients between the naphthol concentrations in urine and the breathing-zone air concentrations of naphthalene were statistically significant, varying in the range of 0.64--0.75 for 1-naphthol and 0.70--0.82 for 2-naphthol. There was linear dependence (r = 0.76) between the summary concentration of naphthols in urine and the naphthalene concentration in air. CONCLUSIONS: Workers in tar distillation and naphthalene distillation are exposed to rather low concentrations of naphthalene and methylated naphthalenes and naphthols. Naphthols and 1,4-naphthoquinone identified in the urine appear to be the products of the hydroxylation of naphthalene present in the breathing-zone air. These findings suggest that the summary concentration of naphthols in urine can be used as a biomarker for naphthalene exposure.

Adolescent↗
PubMed2005

Chemical and electrochemical reduction of polyarene manganese tricarbonyl cations: hapticity changes and generation of syn- and anti-facial bimetallic eta4,eta6-naphthalene complexes.

(Eta6-naphthalene)Mn(CO)(3)(+) is reduced reversibly by two electrons in CH(2)Cl(2) to afford (eta4-naphthalene)Mn(CO)(3)(-). The chemical and electrochemical reductions of this and analogous complexes containing polycyclic aromatic hydrocarbons (PAH) coordinated to Mn(CO)(3)(+) indicate that the second electron addition is thermodynamically easier but kinetically slower than the first addition. Density functional theory calculations suggest that most of the bending or folding of the naphthalene ring that accompanies the eta6 --> eta4 hapticity change occurs when the second electron is added. As an alternative to further reduction, the 19-electron radicals (eta6-PAH)Mn(CO)(3) can undergo catalytic CO substitution when phosphite nucleophiles are present. Chemical reduction of (eta6-naphthalene)Mn(CO)(3)(+) and analogues with one equivalent of cobaltocene affords a syn-facial bimetallic complex (eta4,eta6-naphthalene)Mn(2)(CO)(5), which contains a Mn-Mn bond. Catalytic oxidative activation under CO reversibly converts this complex to the zwitterionic syn-facial bimetallic (eta4,eta6-naphthalene)Mn(2)(CO)(6), in which the Mn-Mn bond is cleaved and the naphthalene ring is bent by 45 degrees . Controlled reduction experiments at variable temperatures indicate that the bimetallic (eta4,eta6-naphthalene)Mn(2)(CO)(5) originates from the reaction of (eta4-naphthalene)Mn(CO)(3)(-) acting as a nucleophile to displace the arene from (eta6-naphthalene)Mn(CO)(3)(+). Heteronuclear syn-facial and anti-facial bimetallics are formed by the reduction of mixtures of (eta6-naphthalene)Mn(CO)(3)(+) and other complexes containing a fused polycyclic ring, e.g., (eta5-indenyl)Fe(CO)(3)(+) and (eta6-naphthalene)FeCp(+). The great ease with which naphthalene-type manganese tricarbonyl complexes undergo an eta6 --> eta4 hapticity change is the basis for the formation of both the homo- and heteronuclear bimetallics, for the observed two-electron reduction, and for the far greater reactivity of (eta6-PAH)Mn(CO)(3)(+) complexes in comparison to monocyclic arene analogues.

Journal Article↗
PubMed1992

Toxicology and Carcinogenesis Studies of Naphthalene (CAS No. 91-20-3) in B6C3F1 Mice (Inhalation Studies).

Naphthalene, a white, crystalline powder, is used as a moth repellent and in the manufacture of phthalic and anthranilic acids, naphthylamines, and synthetic resins. The 2-year studies were conducted by exposing groups of male and female B6C3F1 mice to naphthalene (>99% pure) vapor for 6 hours daily, 5 days per week, for 104 weeks. Genetic toxicology studies were conducted in Salmonella typhimurium and Chinese hamster ovary cells. 2-Year Studies: Groups of male and female mice were exposed to atmospheres containing 0 (75 mice per group), 10 (75 mice per group), or 30 ppm (150 mice per group) naphthalene. Mice from each group were included for 14-day hematology evaluations (male: 0 ppm, 5 animals; 10 ppm, 4; 30 ppm, 10; female: 0 ppm, 4; 10 ppm, 5; 30 ppm, 10). Mean body weights of exposed mice were slightly lower than those of controls throughout the studies. Survival of male control mice was significantly less than that of exposed mice; the lower survival was the result of wound trauma and secondary infections related to fighting among the group-housed mice (0 ppm, 26/70, 37%; 10 ppm, 52/69, 75%; 30 ppm, 118/133, 89%). Survival of exposed female mice was similar to that of controls (59/69, 86%; 57/65, 88%; 102/135, 76%). Neoplastic and Nonneoplastic Effects in the 2-Year Studies: No increase in tumor incidence related to naphthalene administration was observed in male mice. In females, the incidence of pulmonary alveolar/bronchiolar adenomas was significantly greater in the high-dose group than in the controls (5/69, 7%; 2/65, 3%; 28/135, 21%). One other high-dose female had an alveolar/bronchiolar carcinoma. The combined incidence of alveolar/ bronchiolar adenomas and carcinomas in the high-dose females was above those for control female B6C3F1 mice from NTP feed, water, and inhalation studies (91/1,166, 7.8%, range 0%-16%). These lung tumors were attributed to naphthalene exposure. Nonneoplastic lesions attributed to naphthalene exposure were observed in the nose and lungs of mice of both sexes. In the nose, naphthalene exposure was associated with an increase in the incidence and severity of chronic inflammation, metaplasia of the olfactory epithelium, and hyperplasia of respiratory epithelium. Chronic inflammation in the lung was associated with chemical exposure. Genetic Toxicology: Naphthalene was negative for the induction of gene mutations in Salmonella typhimurium strains TA100, TA1535, TA1537, and TA98 with and without exogenous metabolic activation (S9). In cytogenetic tests with Chinese hamster ovary cells, naphthalene induced sister chromatid exchanges with and without S9 activation. Exposure to naphthalene induced a significant increase in chromosomal aberrations in Chinese hamster ovary cells in the presence of S9. Conclusions: Under the conditions of these 2-year inhalation studies, there was no evidence of carcinogenic activity of naphthalene in male B6C3F1 mice exposed to 10 or 30 ppm. There was some evidence of carcinogenic activity of naphthalene in female B6C3F1 mice, based on increased incidences of pulmonary alveolar/ bronchiolar adenomas. In both male and female mice, naphthalene caused increased incidences and severity of chronic inflammation, metaplasia of the olfactory epithelium, and hyperplasia of the respiratory epithelium in the nose and chronic inflammation in the lungs. Synonyms: Naphthalin, Naphthene, Tar Camphor

Journal Article↗
PubMed2001

Specific 16S rDNA sequences associated with naphthalene degradation under sulfate-reducing conditions in harbor sediments.

Previous studies have demonstrated that naphthalene and other polycyclic aromatic hydrocarbons (PAHs) can be anaerobically oxidized with the reduction of sulfate in PAH-contaminated marine harbor sediments, including those in San Diego Bay. In order to learn more about the microorganisms that might be involved in anaerobic naphthalene degradation, the microorganisms associated with naphthalene degradation in San Diego Bay sediments were evaluated. A dilution-to-extinction enrichment culture strategy, designed to recover the most numerous culturable naphthalene-degrading sulfate reducers, resulted in the enrichment of microorganisms with 16S rDNA sequences in the d-Proteobacteria, which were closely related to a previously described pure culture of a naphthalene-degrading sulfate reducer, NaphS2, isolated from sediments in Germany. A more traditional enrichment culture approach, expected to enrich for the fastest-growing naphthalene-degrading sulfate reducers, yielded 16S rDNA sequences closely related to those found in the dilution-to-extinction enrichments and NaphS2. Analysis of 16S rDNA sequences in sediments from two sites in San Diego Bay that had been adapted for rapid naphthalene degradation by continual amendment with low levels of naphthalene suggested that the microbial community composition in the amended sediments differed from that present in the unamended sediments from the same sites. Most significantly, 6-8% of the sequences recovered from 100 clones of each of the naphthalene-amended sediments were closely related to the 16S rDNA sequences in the enrichment cultures as well as the sequence of the pure culture, NaphS2. No sequences in this NaphS2 phylotype were recovered from the sediments that were not continually exposed to naphthalene. A PCR primer, which was designed based on these phylotype sequences, was used to amplify additional 16S rDNA sequences belonging to the NaphS2 phylotype from PAH-degrading sediments from Island End River (Boston), MA, and Liepaja Harbor, Latvia. Closely related sequences were also recovered from highly contaminated sediment from Tampa Bay, FL. These results suggest that microorganisms closely related to NaphS2 might be involved in naphthalene degradation in harbor sediments. This finding contrasts with the frequent observation that the environmentally relevant microorganisms cannot be readily recovered in pure culture and suggests that further study of the physiology of NaphS2 may provide insights into factors controlling the rate and extent of naphthalene degradation in marine harbor sediments.

Biodegradation, Environmental↗
PubMed1998

Naphthalene-induced oxidative stress and DNA damage in cultured macrophage J774A.1 cells.

Naphthalene is a bicyclic aromatic compound that is widely used in various domestic and commercial applications including lavatory scent disks, soil fumigants and moth balls. However, little information is available regarding the mechanism of naphthalene toxicity. We have assessed the concentration-dependent in vitro effects of naphthalene on increased lipid peroxidation, cytochrome c reduction, hydroxyl radical production, modulation of intracellular oxidized states by laser scanning confocal microscopy, and DNA fragmentation in cultured macrophage J774A.1 cells. The cells were incubated with 0-500 microM concentrations of naphthalene for 0, 12 and 24 h at 37 degrees C. Concentration- and time-dependent changes were observed. No significant changes were observed with concentrations of naphthalene up to 100 microM. At 24 h, lipid peroxidation increased by 1.8-, 2.4- and 2.9-fold at 200, 300 and 500 microM concentrations of naphthalene. Approximately 2.0-, 3.1- and 4.6-fold increases in cytochrome c reduction were observed at 200, 300 and 500 microM concentrations of naphthalene, respectively, at this time point demonstrating the production of superoxide anion, while under the same conditions approximately 2.4-, 3.2- and 4.9-fold increases in hydroxyl radical production were observed, respectively. Following incubation of these cells with 200 and 500 microM concentrations of naphthalene 2.3- and 4.7-fold increases in fluorescence intensity were observed, respectively, as compared to the untreated cells. At 24 h, approximately 1.8-, 2.3- and 3.0-fold increases in DNA fragmentation were observed following incubation with 200, 300 and 500 microM concentrations of naphthalene, respectively. Naphthalene also produced concentration- dependent decreases in cell viability. At the 12 h time point, significant changes were observed only with 300 and 500 microM concentrations of naphthalene. These results demonstrate that naphthalene may induce toxic manifestations by enhanced production of oxygen free radicals, resulting in lipid peroxidation and DNA damage.

Animals↗
PubMed2002

Cooxidation of naphthalene and other polycyclic aromatic hydrocarbons by the nitrifying bacterium, Nitrosomonas europaea.

The soil nitrifying bacterium Nitrosomonas europaea has shown the ability to transform cometabolically naphthalene as well as other 2- and 3-ringed polycyclic aromatic hydrocarbons (PAHs) to more oxidized products. All of the observed enzymatic reactions were inhibited by acetylene, a selective inhibitor of ammonia monooxygenase (AMO). A strong inhibitory effect of naphthalene on ammonia oxidation by N. europaea was observed. Naphthalene was readily oxidized by N. europaea and 2-naphthol was detected as a major product (85%) of naphthalene oxidation. The maximum naphthol production rate was 1.65 nmole/mg protein-min in the presence of 240 microM naphthalene and 10 mM NH4+. Our results demonstrate that the oxidation between ammonia and naphthalene showed a partial competitive inhibition. The relative ratio of naphthalene and ammonia oxidation, depending on naphthalene concentrations, demonstrated that the naphthalene was oxidized 2200-fold slower than ammonia at lower concentration of naphthalene (15 microM) whereas naphthalene was oxidized only 100-fold slower than ammonia oxidation. NH4(+)- and N2H4-dependent O2 uptake measurement demonstrated irreversible inhibitory effects of the naphthalene and subsequent oxidation products on AMO and HAO activity.

Acetylene↗
PubMed2005

Consequences of abrupt glutathione depletion in murine Clara cells: ultrastructural and biochemical investigations into the role of glutathione loss in naphthalene cytotoxicity.

Glutathione plays many critical roles within the cell, including offering protection from reactive chemicals. The bioactivated toxicant naphthalene forms chemically reactive intermediates that can deplete glutathione and covalently bind to cellular proteins. Naphthalene selectively injures the nonciliated epithelial cells of the intrapulmonary airways (i.e., Clara cells). This study attempted to define what role glutathione loss plays in naphthalene cytotoxicity by comparing Swiss-Webster mice treated with naphthalene with those treated with the glutathione depletor diethylmaleate. High-resolution imaging techniques were used to evaluate acute changes in Clara cell ultrastructure, membrane permeability, and cytoskeleton structure. A single dose of either diethylmaleate (1000 mg/kg) or naphthalene (200 mg/kg) caused similar glutathione losses in intrapulmonary airways (< 20% of control). Diethylmaleate did not increase membrane permeability, disrupt mitochondria, or lead to cell death--hallmark features of naphthalene cytotoxicity. However, diethylmaleate treatment did cause Clara cell swelling, plasma membrane blebs, and actin cytoskeleton disruptions similar to naphthalene treatment. Structural changes in mitochondria and Golgi bodies also were noted. Changes in ATP levels were measured as an indication of overall cell function, in isolated airway explants incubated with diethylmaleate, naphthalene, or naphthalene metabolites in vitro. Only the reactive metabolites of naphthalene caused significant ATP losses. Unlike the lethal injury caused by naphthalene, the disruptive cellular changes associated with glutathione loss from diethylmaleate seemed to be reversible after recovery of glutathione levels. This suggests that glutathione depletion may be responsible for some aspects of naphthalene cytotoxicity, but it is not sufficient to cause cell death without further stresses.

Actins↗
PubMed1998

Biodegradation kinetics of naphthalene in nonaqueous phase liquid-water mixed batch systems: comparison of model predictions and experimental results.

A model is formulated to describe dissolution of naphthalene from an insoluble nonaqueous phase liquid (NAPL) and its subsequent biodegradation in the aqueous phase in completely mixed batch reactors. The physicochemical processes of equilibrium partitioning and mass transfer of naphthalene between the NAPL and aqueous phases were incorporated into the model. Biodegradation kinetics were described by Monod's microbial growth kinetic model, modified to account for the inhibitory effects of 1,2-naphthoquinone formed during naphthalene degradation under certain conditions. System parameters and biokinetic coefficients pertinent to the NAPL-water systems were determined either by direct measurement or from nonlinear regression of the naphthalene mineralization profiles obtained from batch reactor tests with two-component NAPLs comprised of naphthalene and heptamethylnonane. The NAPLs contained substantial mass of naphthalene, and naphthalene biodegradation kinetics were evaluated over the time required for near complete depletion of naphthalene from the NAPL. Model predictions of naphthalene mineralization time profiles compared favorably to the general trends observed in the data obtained from laboratory experiments with the two-component NAPL, as well as with two coal tars obtained from the subsurface at contaminated sites and composed of many different PAHs (polycyclic aromatic hydrocarbon compounds). The effects of varying the NAPL mass and the naphthalene mole fractions in the NAPL are discussed. It was observed that the time to achieve a given percent removal of naphthalene does not change significantly with the initial mass of naphthalene in a fixed volume of the NAPL. Significant changes in the mineralization profiles are observed when the volume (and mass) of NAPL in the system is changed.

Biodegradation, Environmental↗
PubMed2002

Solid-state fluorescence study of naphthalene adsorption on porous material.

Naphthalene adsorption profile on porous materials was studied using solid-state fluorescence spectroscopy. When naphthalene crystals were simply mixed with porous crystalline cellulose (PCC), excimer emission of naphthalene was observed after 1 min of mixing, suggesting a drastic change in the naphthalene molecular environment during the mixing procedure. For the naphthalene-octadesyl silane (ODS)-80A or naphthalene-ODS-2 systems, the changes in adsorption profiles and fluorescence spectral pattern of naphthalene were similar to those of the naphthalene-PCC system. The final amounts of naphthalene adsorbed to ODS-80A and ODS-2 were 0.05 and 0.024 g/g adsorbent, respectively, even though the two materials had comparable values of specific surface area. The relative emission intensity (I(excimer)/I(monomer)) in the ODS-80A system was higher than that in the ODS-2 system when compared at the same amount of naphthalene adsorbed. It was concluded that the pore size of porous materials affected the naphthalene excimer formation on the surface.

Adsorption↗
PubMed2000

Quantification of individual glutathione S-transferase isozymes in hepatic and pulmonary tissues of naphthalene-tolerant mice.

Acute exposure to naphthalene produces severe bronchiolar epithelial cell necrosis in mice, whereas subchronic exposure to naphthalene (200 mg/kg/7 days) fails to produce epithelial necrosis and renders the animals tolerant to subsequent challenge doses of naphthalene. Mechanisms responsible for the development of tolerance have not been delineated. The few studies exploring naphthalene tolerance focus on expression of microsomal enzymes and have yet to delve into expression of the hepatic detoxification enzymes such as glutathione S-transferases (GSTs; EC 2.5.1.18). Glutathione conjugation catalyzed by GSTs accounts for one of the two primary routes of naphthalene detoxification. In this study, we rigorously quantify levels of individual GST isozymes expressed within the livers and lungs of mice with acquired tolerance to naphthalene. Subchronic exposure to naphthalene increases the abundance of some hepatic GSTs to levels as much as 68% greater than controls. Naphthalene-tolerant mice displayed increases in mGSTM1 (51%), mGSTM2 (58%), and mGSTP1 (66%), whereas no significant difference in mGSTA3 was observed between exposed and control mice. Extracts of pulmonary tissues from naphthalene-tolerant mice showed minor increases in levels of mGSTP1 (7%) and Peak 8 isozyme (27%) and decreases in levels of mGSTM1 (31%), mGSTM2 (17%), and mGSTA3 (8%). The total enzymatic activity for the conjugation of 1-chloro-2,4-dinitrobenzene (CDNB) was 22% lower in lung extracts from naphthalene-tolerant animals than in controls. These results indicate that induction of hepatic GSTs is substantial and may be an important factor in the development of tolerance to naphthalene.

Animals↗
PubMed1992

Establishment of a naphthalene cataract model in vitro.

In the past, almost all studies on naphthalene cataract were based on in vivo experiments. Such studies are laborious and time-consuming and are complicated by systemic toxicity arising from the metabolites of naphthalene. In order to study the direct effects of naphthalene metabolites on the lens, we established an in vitro 'naphthalene cataract' model system by exposing rat lens to naphthalene dihydrodiol (2.5 x 10(5) M) containing medium for 48 hr. Under these conditions, we analysed several biochemical parameters including the glutathione level, protein mixed disulfides, protein patterns on SDS-gels, active transport, NA+/K(+)-ATPase activities and the measurement of naphthalene metabolites in the cultured lenses. The results showed that both the morphological and biochemical changes were very similar to those observed in lenses of rats fed naphthalene (1 g kg-1 day-1). Furthermore, ALO1576 completely blocked the in vitro changes as it did in vivo. Therefore, this model system can be used as a new tool to investigate the mechanism of naphthalene cataract formation. Other naphthalene metabolites such as 1-naphthol, 2-naphthol, 1,2-dihydroxynaphthalene and 1,2-naphthoquinone were also studied in vitro and the results showed that the effects of these naphthalene metabolites were very different from those observed in naphthalene cataracts in vivo.

Aldehyde Reductase↗
PubMed1989

Tolerance to multiple doses of the pulmonary toxicant, naphthalene.

Intraperitoneal administration of single doses of the volatile aromatic hydrocarbon, naphthalene, resulted in dose-dependent bronchiolar epithelial cell necrosis in mice. Twenty-four hours after a dose of 50 mg/kg, swelling of Clara cells with some exfoliation of epithelial cells was evident in half of the treated animals. At doses of 100 mg/kg small numbers of necrotic and swollen cells with pyknotic nuclei were observed. At 200 mg/kg there were substantial numbers of bronchiolar epithelial cells sloughed into the airway lumen, apical projections were virtually absent, and there were large numbers of cells with pyknotic nuclei. In contrast, bronchiolar airways from mice treated with naphthalene daily for 7 days at doses of 50, 100, or 200 mg/kg/day differed only slightly from controls. Significant protection to bronchiolar epithelial cell necrosis produced by 300 mg/kg naphthalene was afforded by seven daily injections of 200 but not 50 or 100 mg/kg naphthalene. A gradual recovery in sensitivity to the 300 mg/kg challenge dose of naphthalene was observed as the time between the last 200 mg/kg naphthalene dose increased from 24 to 144 hr. Daily administration of 200 mg/kg but not 50 or 100 mg/kg naphthalene for 7 days resulted in a selective decrease in the rate of formation of 1R,2S-naphthalene oxide by mouse lung but not liver microsomal enzymes. This selective decrease in pulmonary microsomal formation of 1R,2S-oxide continued in animals killed 48, 96, and 144 hr after the last administration of 200 mg/kg. Alterations in the rate of formation of reactive, covalently bound naphthalene metabolites in lung microsomes were not observed, nor were there any differences in the levels of covalently bound reactive metabolites in vivo between tolerant and control animals. These studies are consistent with other work showing that the lung loses susceptibility to the acute injury arising from repeated exposure to pneumotoxicants. In contrast to other studies with naphthalene where alterations in the levels of covalently bound reactive metabolites in the lung closely paralleled the extent and severity of bronchiolar injury, these studies clearly separate necrosis from covalent binding. Although the correlation was not absolute, it appears that formation of 1R,2S-oxide by microsomal enzymes in vitro is a better overall marker of decreased sensitivity to naphthalene-induced bronchiolar necrosis than is reactive metabolite binding either in vivo or in vitro.

Animals↗
PubMed2003

Importance of Gram-positive naphthalene-degrading bacteria in oil-contaminated tropical marine sediments.

AIMS: The aim of this study was to isolate, characterize and evaluate the importance of naphthalene-degrading bacterial strains from oil-contaminated tropical marine sediments. METHODS AND RESULTS: Three Gram-positive naphthalene-degrading bacteria were isolated from oil-contaminated tropical intertidal marine sediments by direct isolation or enrichment using naphthalene as the sole source of carbon and energy. Bacillus naphthovorans strain MN-003 can also grow on benzene, toluene, xylene and diesel fuel while Micrococcus sp. str. MN-006 can also grow on benzene. Staphylococcus sp. str. MN-005 can only degrade naphthalene and was not able to use the other aromatic hydrocarbons tested. Strain MN-003 possessed the highest maximal specific growth rate with naphthalene as sole carbon source. An enrichment culture fed with naphthalene as sole carbon source exhibited a significant increase in the relative abundances of the three isolates after 21 days of incubation. The three isolates constituted greater than 69% of the culturable naphthalene-degrading microbial community. Strain MN-003 outcompeted and dominated the other two isolates in competition studies involving batch cultures inoculated with equal cell densities of the three isolates and incubated with between 1 and 10 mg l-1 of naphthalene. CONCLUSIONS: Three Gram-positive naphthalene-degrading bacteria were successfully isolated from oil-contaminated tropical marine sediments. Gram-positive bacteria might play an important role in naphthalene degradation in the highly variable environment of oil-contaminated tropical intertidal marine sediments. Among the three isolates, strain MN-003 has the highest maximal specific growth rate when grown on naphthalene, and outgrew the other two isolates in competition experiments. SIGNIFICANCE AND IMPACT OF THE STUDY: This research will aid in the development of bioremediation schemes for oil-contaminated marine environments. Strain MN-003 could potentially be exploited in such schemes.

Bacillus↗