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At least 973 records · Page 54Linked to original sources
PubMed2002

Electrochemical detection of nucleic base mismatches with ferrocenyl naphthalene diimide.

Electrochemical detection of nucleic base mismatches was attempted successfully with ferrocenyl naphthalene diimide (FND) in a model system with 20-meric double-stranded oligonucleotides with or without a mismatch(es). Thus, dA(20) or a 20-meric sequence of the lac Z gene was immobilized on a gold electrode and complementary oligonucleotides with different numbers of mismatches were allowed to hybridize in the presence of FND to give rise to an electrochemical signal. The signal intensity varied depending on the number of unpaired bases on the DNA duplex. From experiments with a quartz crystal microbalance, eight molecules of FND were found to bind to the 20-meric double-stranded oligos and this number decreased as the number of mismatches increased. These findings were further supported by matrix-assisted laser desorption ionization time-of-flight mass spectroscopy. This novel method will be useful for the analysis of single-nucleotide polymorphisms present on human genes.

Base Pair Mismatch↗
PubMed1997

Purification and crystallization of the oxygenase component of naphthalene dioxygenase in native and selenomethionine-derivatized forms.

A new procedure was developed for the purification of the terminal oxygenase component (ISPNAP) of naphthalene dioxygenase. From a five liter culture of Escherichia coli JM109(DE3)(pDTG121), 91 mg of pure protein were obtained with a specific activity of 2.48 mumol/ min/mg protein. ISPNAP was crystallized in the rhombohedral space group R32 with cell dimensions of a = b = 179.2 A; c = 322.5 A in the hexagonal setting. The crystals are brown, indicating the presence of an intact Rieske iron-sulfur center. Problems with non-isomorphism between native data sets necessitated the preparation of a selenomethionine-substituted protein. Complete replacement of methionine with selenomethionine was achieved and the purified protein had a specific activity almost identical to native ISPNAP. Crystals from this preparation belong to the same space group and have similar cell dimensions to native ISPNAP.

Crystallography, X-Ray↗
PubMed2001

Effect of beta-Cyclodextrin on the Photoinduced Charge Transfer in Sodium 1-Anilino-8-naphthalene Sulfate (ANS)/CdS Colloidal System.

The S-center radical (ANS(.)) of sodium 1-anilino-8-naphthalene sulfate (ANS) generated by photoinduced charge transfer in ANS/CdS and ANS/CdS/beta-cyclodextrin(beta-CD) systems has been studied by using spin trapping electron spin resonance techniques, UV-visible spectroscopic methods, and fluorescence spectroscopic methods. It was found that the S-centered radical (ANS(.)) was produced by the charge transfer reaction between the ground state ANS and the positive hole h(+)(CdS) from the valence band of CdS colloids, by the charge transfer from the excited singlet state (1)ANS* to the conduction band of CdS colloids, or by both in the ANS/CdS and ANS/CdS/beta-CD systems. The ESR signal intensity of the spin adduct (5,5'-dimethyl-1-pyrroline-N-oxide (DMPO)-ANS)(.), which is formed from ANS(.) trapped by DMPO, in the latter system is 15 times stronger than that in the former system. The apparent association constants between ANS and CdS colloids in the absence and presence of beta-CD determined from fluorescence quenching experiments are 1097 and 1606 M(-1), respectively. From ESR and fluorescence results, it is estimated that the efficiency of photoinduced charge transfer from ANS to CdS colloids in the ANS/CdS/beta-CD system is 12.5 times that in the ANS/CdS system. Copyright 2001 Academic Press.

Journal Article↗
PubMed1993

Membrane permeability transition promoted by phosphate enhances 1-anilino-8-naphthalene sulfonate fluorescence in calcium-loaded liver mitochondria.

Phosphate and a number of other compounds induce membrane permeability transition (MBT) in Ca(2+)-loaded mitochondria. 1-Anilino-8-naphthalene sulfonate (ANS) was used as a fluorescent probe to investigate perturbations on the inner membrane during MBT. Induction of MBT caused ANS fluorescence enhancement with a biphasic rate that reached a plateau. The enhancement is analogous to that reported for de-energization of mitochondria. The fluorescence level was independent of whether ANS was added before or at different times after phosphate. In the absence of ANS, fluorescence was low and remained unchanged. The initial time course of MBT, as followed by large-amplitude swelling, was similar to that of fluorescence enhancement. Ruthenium red, EGTA, ADP, and cyclosporin A inhibited the enhancement. Only EGTA + ADP (or ATP) reversed the enhancement when added after phosphate. Efflux of matrix Ca2+ by sodium acetate or A23187 did not alter ANS fluorescence. The binding parameters (Kd and number of binding sites) were not significantly different, but the fluorescence maximum was more than doubled after MBT. Although the fluorescence of bound ANS showed a nonlinear relationship, it was always higher (73.0 +/- 19.0%) after reaching the plateau. Since ANS binding to membranes is nonspecific, the exact mechanism of the enhanced fluorescence is not apparent. The dependence of the initial rate of fluorescence enhancement on Ca2+ concentration was nonlinear, with 45 microM at half-maximal rate. The dependence on phosphate was hyperbolic with 0.7 mM at half-maximal rate, which is close to the Km value of phosphate carrier. The kinetics is compatible with Ca2+ binding to some membrane component(s) during MBT and cause ANS fluorescence enhancement.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1990

Kinetic analysis of the dose-dependent hepatic handling of 1-anilino-8-naphthalene sulfonate in rats.

The dose dependency in the hepatic transport of an anionic fluorescent dye, 1-anilino-8-naphthalene sulfonate (ANS), was investigated by measuring the plasma disappearance and biliary excretion in rats. Bulk of the administered ANS distributed into the liver at 10 min after iv bolus injection. The plasma disappearance curves of ANS were then kinetically analyzed based on a two-compartment model, in which the ligand is eliminated only from the peripheral compartment (liver compartment). The total body clearance (CLtot) decreased with increasing dose of ANS. That is, the values of CLtot were 4.06 and 1.98 ml/min/per kg at the doses of 3 and 100 mumol/kg, respectively. The clearances of the uptake and sequestration processes (CLup and CLseq, respectively) for a total ligand were constant irrespective of dose, while the efflux clearance (CLeff) for a total ligand was increased by twofold with increasing dose. A mechanism for the increase in the CLeff value might be explained by a saturation of the ANS binding to the intracellular proteins. The hepatocellular distribution and the binding of ANS to cytosolic proteins were then determined. ANS mainly distributed to the cytosol fraction, and the unbound fraction in the cytosol increased from approximately 0.04 to 0.09 when the cytosolic concentrations of ANS increased from 40 to 900 microM, respectively. In spite of such increase in the unbound fraction in the cytosol, the CLseq values remained unchanged with increasing dose, suggesting that the saturation of sequestration clearance for unbound ANS might occur. Furthermore, the plasma disappearance curves of ANS at various doses were simultaneously analyzed based on three nonlinear kinetic models: Model I is a model incorporating both saturable intracellular binding and saturable sequestration; Model II is a model incorporating only saturable intracellular binding; Model III is the model incorporating only saturable sequestration. Goodness-of-fit evaluated by AIC value was best for Model I. Taken together, the nonlinearity in the plasma clearance of ANS was confirmed to be attributed to saturation of both its binding to cytosolic proteins and sequestration process.

Anilino Naphthalenesulfonates↗
PubMed1977

Use of 1-anilino-8-naphthalene-sulfonate as a probe of gastric vesicle transport.

The interaction of 1-anilino-8-naphthalene-sulfonate (ANS) with vesicles derived from hog fundic mucosa was studied in the presence of valinomycin and with the addition of ATP. Evidence was found for two classes of sites, those rapidly accessible to ANS with a KD of 7.5 micronM and those slowly accessible, but rapidly accessed in the presence of valinomycin with a KD of 2.5 micronM. ATP transiently increases the quantum yield of the latter ANS binding sites only in the presence of valinomycin, but does not alter the number of KD of those sites. The time course of this increase correlates with H+ uptake and Rb+ extrusion by those vesicles and H+ carries such as tetrachlorsalicylanilide or nigericin abolish the ATP response. With ATP addition in the presence of SC14N and valinomycin there is transient uptake of SCN-. It is concluded that ANS is acting as a probe of a structural change dependent on a potential and H+ gradient.

Anilino Naphthalenesulfonates↗
PubMed1998

Metabolism of an anionic fluorescent dye, 1-anilino-8-naphthalene sulfonate (ANS) by rat liver microsomes.

The present study was designed to examine the metabolism of 1-anilino-8-naphthalene sulfonate (ANS), an anionic compound which is transported into liver via "multispecific organic anion transporter", with rat hepatic microsomes. TLC analysis indicated that the fluorescent metabolites were not produced to a measurable extent, which made it possible to assess the ANS metabolism by measuring the fluorescence disappearance. The metabolism of ANS was remarkably inhibited by the presence of SKF-525A as well as by the substitution of O2 by CO gas. ANS metabolism by microsomes also required NADPH as a cofactor. These results indicated that the microsomal monooxygenase system might be mainly responsible for the ANS metabolism. The maximum velocity (Vmax) and Michaelis constant (K(m)) were calculated to be 4.3 +/- 0.2 nmol/min/mg protein and 42.1 +/- 2.0 microM, respectively. Assuming that 1 g of liver contains 32 mg of microsomal protein, the Vmax value was extrapolated to that per g of liver (Vmax'). The intrinsic metabolic clearance (CLint) under linear conditions calculated from this in vitro metabolic study was 3.3 ml/min/g liver, being comparable with that (3.0 ml/min/g liver) calculated by analyzing the in vivo plasma disappearance curve in a previous study. Furthermore, the effects of other organic anions on the metabolism of ANS were examined. Bromophenolblue (BPB) and rose bengal (RB) competitively inhibited the metabolism of ANS, while BSP inhibited it only slightly. The inhibition constant (Ki) of BPB (6 microM) was much smaller than that of RB (200 microM). In conclusion, the microsomal monooxygenase system plays a major role in the metabolism of ANS, and other unmetabolizable organic anions (BPB and RB) compete for this metabolism.

Anilino Naphthalenesulfonates↗
PubMed2003

Kinetic analysis about the bidirectional transport of 1-anilino-8-naphthalene sulfonate (ANS) by isolated rat hepatocytes.

The purpose of the present study was to investigate the bidirectional transport of 1-anilino-8-naphthalene sulfonate (ANS) using isolated rat hepatocytes. The initial uptake rate of ANS by isolated hepatocytes was determined. The uptake process of ANS was saturable, with a Km of 29.1 +/- 3.2 microM and Vmax of 2.9 +/- 0.1 mmol/min/mg protein. Subsequently, the initial efflux rate of ANS from isolated hepatocytes was determined by resuspending preloaded cells to 3.0% (w/v) BSA buffer. The efflux process for total ANS revealed a little saturability. The mean value of the efflux clearance was 2.2 +/- 0.1 microL/min/mg protein. The efflux rate of ANS from hepatocytes was markedly decreased at 4 degrees C, indicating that the apparent efflux of ANS might not be attributed to the release of ANS bound to the cell surface, but to the efflux of ANS from intracellular space. The efflux clearance was furthermore corrected for the unbound intracellular ANS concentration on the basis of its binding parameters to cytosol. The relation between efflux rate and unbound ANS concentration was fitted well to the Michaelis-Menten equation with a saturable and a nonsaturable components. The Vmax and Km values were 0.54 mmol/min/mg protein, and 10.0 microM, respectively. Based on the comparison of the ratios of Vmax to Km (Vmax/Km) corresponding to the transport clearance, the influx clearance was two times higher than the efflux clearance. Together with our preliminary studies that ATP suppression in hepatocytes substantially inhibited ANS influx rate, we concluded that the hepatic uptake of ANS is actively taken up into hepatocytes via the carrier mediated transport system.

Anilino Naphthalenesulfonates↗
PubMed2000

Identification of chemical substances by testing and screening of hypotheses. II. Determination of impurities in n-hexane and naphthalene.

The impurities in n-hexane and naphthalene are identified by gas chromatography and mass spectrometry when applying the multiple criteria of identification. The identification uncertainty is expressed by the significance level, the difference in retention indexes and the mass spectra fit value. Identified impurities are substances which are rather abundant in nature/practice/research and rather frequently co-cited with matrix substance in chemical literature. This regularity is discussed with reference to statistical treatment of chemical database as a means to screen identification hypotheses.

Journal Article↗
PubMed1999

Functionality of biphenyl 2,3-dioxygenase components in naphthalene 1,2-dioxygenase.

Naphthalene 1,2-dioxygenase (Nap dox) and biphenyl 2,3-dioxygenase (Bph dox) are related enzymes that have differentiated during evolution as their specificity has changed. Although their component arrangement is similar, the structure of each component has been modified quite extensively. The purpose of this work was to determine the catalytic capacity of purified Nap dox toward chlorobiphenyls and to investigate the functionality of Bph dox components in the Nap dox system. Both enzyme systems were purified by affinity chromatography as histidine-tagged fused proteins. Data show for the first time that Nap dox can catalyze the oxygenation of all three monochlorobiphenyl isomers, but it is unable to hydroxylate 2,5-, 2,2'-, 3,3'-, 4,4'-di- and 2,2',5,5'-tetrachlorobiphenyl. The rates of cytochrome c reduction by the ferredoxin components of the two enzymes were identical when the Bph dox reductase component was used in the assay, showing an efficient electron transfer between the Bph dox reductase component and the Nap dox ferredoxin. However, when the Bph dox ferredoxin was used to reconstitute a hybrid Nap dox, the enzyme was only 22% as active as the parental enzyme. These data are discussed in terms of the potential use of Nap dox for the development of enhanced chlorobiphenyl-degrading dioxygenases.

Dioxygenases↗
PubMed2006

Biological monitoring of exposure to 1,5-naphthalene diisocyanate and 4,4'-methylenediphenyl diisocyanate.

OBJECTIVES: Biological monitoring of occupational sensitizers, such as 1,5-naphthalene diisocyanate (NDI) and 4,4'-methylenediphenyl diisocyanate (MDI) is of high importance. In this study, 1,5-naphthalenediamine (NDA) and 4,4'-methylenedianiline (MDA) in hydrolysed urine and plasma were evaluated as biomarkers of exposure to NDI and MDI, respectively. METHODS: The air exposure to NDI and MDI was monitored for 30 exposed workers at four different plants. In parallel, urinary as well as blood plasma samples were collected. Biomarker levels were determined in hydrolysed urine and plasma by means of gas chromatography-mass spectrometry. RESULTS: Air exposure to both MDI and NDI was correlated to their corresponding urinary and plasma biomarkers. The correlation coefficients for the associations between air and biomarker levels were in the range of 0.51-0.65 and 0.53-0.96 for MDI and NDI, respectively. For NDI, but not for MDI, the significance and correlation coefficients were increased by adjusting the urinary biomarker levels for creatinine content or density. CONCLUSIONS: Biomarker and air levels of MDI and NDI were correlated, but there was a large individual variation.

Air Pollutants, Occupational↗
PubMed2005

NO binding to naphthalene dioxygenase.

Nitric oxide (NO) is commonly used as an analogue for dioxygen in structural and spectroscopic studies of oxygen binding and oxygen activation. In this study, crystallographic structures of naphthalene dioxygenase (NDO) in complex with nitric oxide are reported. In the presence of the aromatic substrate indole, NO is bound end-on to the active-site mononuclear iron of NDO. The structural observations correlate well with spectroscopic measurements of NO binding to NDO in solution. However, the end-on binding of NO is in contrast to the recently reported structure of oxygen to the active-site iron of NDO that binds side-on. While NO is a good oxygen analogue with many similarities to O(2), the different binding mode of NO to the active-site iron atom leads to different mechanistic implications. Hence, caution needs to be used in extrapolating NO as an analogue to O(2) binding.

Binding Sites↗
PubMed2005

Biodegradation of naphthalene-2-sulfonic acid present in tannery wastewater by bacterial isolates Arthrobacter sp. 2AC and Comamonas sp. 4BC.

Two bacterial strains, 2AC and 4BC, both capable of utilizing naphthalene-2-sulfonic acid (2-NSA) as a sole source of carbon, were isolated from activated sludges previously exposed to tannery wastewater. Enrichments were carried out in mineral salt medium (MSM) with 2-NSA as the sole carbon source. 16S rDNA sequencing analysis indicated that 2AC is an Arthrobacter sp. and 4BC is a Comamonas sp. Within 33 h, both isolates degraded 100% of 2-NSA in MSM and also 2-NSA in non-sterile tannery wastewater. The yield coefficient was 0.33 g biomass dry weight per gram of 2-NSA. A conceptual model, which describes the aerobic transformation of organic matter, was used for interpreting the biodegradation kinetics of 2-NSA. The half-lives for 2-NSA, at initial concentrations of 100 and 500 mg/l in MSM, ranged from 20 h (2AC) to 26 h (4BC) with lag-phases of 8 h (2AC) and 12 h (4BC). The carbon balance indicates that 75-90% of the initial TOC (total organic carbon) was mineralized, 5-20% remained as DOC (dissolved organic carbon) and 3-10% was biomass carbon. The principal metabolite of 2-NSA biodegradation (in both MSM and tannery wastewater) produced by Comamonas sp. 4BC had a MW of 174 and accounted for the residual DOC (7.0-19.0% of the initial TOC and 66% of the remaining TOC). Three to ten percent of the initial TOC (33% of the remaining TOC) was associated with biomass. The metabolite was not detected when Arthrobacter sp. 2AC was used, and a lower residual DOC and biomass carbon were recorded. This suggests that the two strains may use different catabolic pathways for 2-NSA degradation. The rapid biodegradation of 2-NSA (100 mg/l) added to non-sterile tannery wastewater (total 2-NSA, 105 mg/l) when inoculated with either Arthrobacter 2AC or Comamonas 4BC showed that both strains were able to compete with the indigenous microorganisms and degrade 2-NSA even in the presence of alternate carbon sources (DOC in tannery wastewater = 91 mg/l). The results provide information useful for the rational design of bioreactors for tannery wastewater treatment.

Arthrobacter↗
PubMed2005

Analysis of the effects of protic, aprotic, and multi-component solvents on the fluorescence emission of naphthalene and its exciplex with triethylamine.

The emission spectra of naphthalene (NP)-triethylamine (TEA) systems were measured under steady-state illumination conditions in some protic and aprotic solvent-tetrahydrofuran (THF) mixtures. The fluorescence spectrum of the NP-TEA system in THF could be separated into two component bands (band A at 329 nm (fluorescence of NP) and band B at 468 nm (emission from an intermolecular exciplex)). The intensities of bands A and B decreased with increasing solvent polarity. The intensity of band B also decreased owing to the hydrogen-bonding interaction between TEA and protic solvents, but in this case the intensity of band A increased. The decrease in the intensity of band A with increasing solvent polarity is considered to be caused by the enhanced formation of an ion-pair parallel to the formation of an exciplex with increasing solvent polarity. The decrease in the intensity of band B is considered to be caused by the enhanced formation of ion-pair both parallel to and through the formation of the exciplex. The increase in the intensity of band A and the decrease in that of band B upon the addition of protic solvents is caused by the decrease in the concentration of free TEA. Acetonitrile only has a polar effect and trichloroacetic acid only has a hydrogen-bonding (protonation) effect, while alcohols have both the effects.

Journal Article↗
PubMed1988

The binding of 8-anilino-1-naphthalene sulfonate (ANS) to fish myosin and the effect of salts on the thermal transitions of fish myosin-ANS complex.

Myosin prepared from tilapia (Serotherodon aureus) was complexed with 8-anilino-1-naphthalene sulfonate (ANS) and continuously heated at 1 degree C/min. A large increase in fluorescence was observed with a transition temperature of 34 degrees C. The effect of several salts on the transition temperature was tested. A plot based on the equation of E. E. Schrier and E. B. Schrier [(1967) J. Phys. Chem. 71, 1851-1860] gave a value of less than or equal to 500 cal/mol-deg for the change in enthalpy per residue due to exposure to solvent. The ratio of hydrophobic group to amide group exposure to solvent was intermediate compared with the ratio of RNase and gelatin. Fluorescence titrations yielded one high affinity site with a Kb of 2 X 10(6) M-1 and at least 200 low affinity sites with an average value of 1 X 10(5) M-1. The parameters did not change significantly with temperature. We propose that the increase in ANS fluorescence reflects changes in conformation of myosin as monitored by these low affinity sites, resulting in an increase in surface hydrophobicity and representing a small enthalpic change in the conformation of the myosin molecule. As a consequence, the change in conformation accelerates polymerization of myosin oligomers.

Anilino Naphthalenesulfonates↗
PubMed1978

Changes in fluorescence of 8-anilino-1-naphthalene sulfonate after bacteriophage T5 infection of Escherichia coli. Initial fluorescence rise coincides with onset of rubidium efflux.

Escherichia coli cells pre-loaded with 86Rb+ begin to lose 86Rb+ immediately after phage T5 addition. The loss proceeds with negative-exponential (first-order) kinetics for up to approximately 15 min after phage addition. The constant which characterizes the rate of loss increases with increasing numbers of infecting phage per cell. It is known that anaerobic, fermenting cells of E. coli show a two-step increase in 8-anilino-1-naphthalene sulfonate (ANS) fluorescence upon infection with bacteriophage T5; the first rise begins immediately upon phage addition, the second 6 min later. The onset of 86Rb+ release, therefore, is correlated with the first fluorescence rise with respect to timing and response to the multiplicity of infection.

Aerobiosis↗
PubMed1985

Reciprocal effects of phenothiazines and naphthalene sulfonamides on the external ATP-dependent permeability change in Chinese hamster ovary cells.

External ATP causes a great increase in passive permeability to phosphorylated metabolites in several transformed cells, but not in untransformed cells. We have previously demonstrated that the external ATP-dependent permeability change was induced in Chinese hamster ovary cells, CHO-K1, only in the presence of a mitochondrial inhibitor (rotenone, KCN) or a cytoskeleton-attacking agent, vinblastine (Kitagawa, T. and Akamatsu, Y. Biochim. Biophys. Acta 649, 76-82 (1981); 734, 25-32 (1983]. A similar ATP-dependent permeability change was also induced in CHO cells when the cells were treated with 10-30 microM trifluoperazine. This permeability change, like the previously mentioned ones, was found to be reversible and the treated cells remained viable. The permeability change induced by ATP and trifluoperazine was independent of changes in cellular ATP concentration and this property was the same as that of the permeability change with external ATP and vinblastine. Since trifluoperazine is known to interact with calmodulin and to inhibit calmodulin-dependent cellular functions, these results may indicate that calmodulin associated with the cytoskeleton plays an important role in control of the permeability change, although nonspecific perturbation by the drug of the membranes cannot be ruled out. Chlorpromazine and a naphthalene sulfonamide, W-7, also induced an ATP-dependent permeability change. However, these drugs, like mitochondrial inhibitors, reduced the cellular ATP concentration to induce the permeability change. Thus, a clear difference in the action of these drugs in intact cells was also shown in this study. Possible mechanisms for the ATP-dependent permeability change in mammalian cells are discussed.

Adenosine Triphosphate↗